The opinion of the court was delivered by
Weiftkaub, C. J.
Defendant, a licensed physician of this State, was indicted for the involuntary manslaughter of 3 5 of his patients. He was convicted on 12 counts and acquitted on the other three. He was sentenced to two to four years in the New Jersey State Prison and fined $1,000 on each conviction, the sentences to run concurrently. We certified his appeal before the Appellate Division considered it.
Defendant’s specialty is neuropsychiatry. His treatments included intravenous injections of certain drugs and also the infusion intravenously of a saline solution and a surital solution. The State’s thesis was that death was caused by serum hepatitis transmitted into the blood stream by these injections and infusions.
The case is unusual. It is unusual in that a physician is charged with crime in pursuing procedures he intended to aid the patient. It is unusual in that there was a common trial [23]*23of 15 charges arising out of separate events, and the State’s proof included as well evidence of the alleged infection of 35 additional patients who recovered. It is unusual in that the State was unable to prove what precise failure or misconduct transmitted the fatal disease. The issues on this appeal arise from these circumstances, and to see them in perspective, the nature of the disease and the state of medical knowledge must be understood.
Hepatitis is an inflammation of the liver. It may come from sundry causes. Three forms figure largely in this case. One, called “toxic” hepatitis, is caused by certain drugs or chemicals and we gather is noncontagious. The other two, attributed to a virus, are called “viral” hepatitis. One form of viral hepatitis is “infectious” hepatitis and is communicated or transmitted by the fecal-oral route. The other form of viral hepatitis is “serum” hepatitis, and this is transmitted directly into the blood stream by the injection of contaminated material. The State’s ease depended upon the thesis that the decedents died of serum hepatitis, transmitted into their veins by the injections and infusions which we have already mentioned and which we will shortly describe.
The important fact to be noted is that although infectious hepatitis and serum hepatitis are deemed to be viral, the offending virus or viruses, if there are more than one, have not been isolated and hence have never been cultured. Accordingly there is no way to detect the virus by examination of equipment or drug or solution. Indeed there are carriers of the disease who reveal no evidence of it and who cannot be uncovered by any test. Dr. Hans Popper, produced by the State as a leading authority on diseases of the liver, testified:
“I would like to state that we cannot culture the virus, that is the only way how we can obtain information about—definite information about the existence of virus, is by establishing in a human volunteer that the certain material is infectious. Obviously there are tremendous limitations in doing so. This is the reason for our limited knowledge of viral hepatitis. This is the reason why I am forced to answer many questions I don’t know, I don’t think so, it may be so.”
[24]*24Dr. Alexander Duncan Langmuir, Chief Epidemiologist of the Communicable Disease Center of the United States Public Health Service, said:
“* * * The infectious hepatitis in the last four or five years has become one where we have become increasingly realizing how important the total problem is. In addition to the routine reports which are put out each week, we put out rather extensive surveillance reports to specialized persons.”
Further, even upon pathological examination of the liver tissue it apparently cannot be told whether the hepatitis is infectious or serum. Thus upon autopsy in any given case all that can be said is that the hepatitis is viral in nature. Whether the disease is the infectious type or the serum type can be only inferred from a survey of a much larger scene and by finding in that scene evidence of the known differences between the two viral hepatitises. One such difference is that the rate of fatality is distinctly higher in the case of serum hepatitis. Another is that the incubation period with respect to infectious hepatitis is two to six weeks, while the period in the case of serum hepatitis is six weeks to six months, or, according to some testimony, as much as one year.
Here the incidence of viral hepatitis among defendant’s patients, when contrasted with the incidence of the disease in the locality, convincingly pointed to defendant’s office as the place where the infection was transmitted; and that the hepatitis was serum, rather than infectious, was inferable from the rate of fatality, and also, at least in the view of an epidemiologist produced by the State, from the incubation pattern which he found in the dates of illnesses of the 40 patients to whom we have referred. And of course the circumstances that all of the victims received intravenous injections or infusions supplied the final fact without which the diagnosis of serum hepatitis could not have been made.
The record would well warrant a finding that serum hepatitis was transmitted in defendant’s practice. We do not mean that there was no serious issue of fact as to the cause of [25]*25death of the 15 patients. There was considerable conflict in expert evaluation of the post-mortem findings, and the jury probably acquitted the defendant of three of the charges because it was not convinced that the deaths therein involved were due to serum hepatitis.
I.
We of course must keep in mind that this is a criminal case. In a civil action for damages, the question is whether a loss shall remain where it fell or be shifted to him whose act brought it about. The test there is ordinary negligence—-the failure to behave as would a reasonable man in such circumstances. The issue being only whether the victim or the actor shall bear the dollar impact, the law goes far in permitting the trier of the facts to “infer” both fault and causal connection between the fault and the loss. Indeed, if the total circumstances bespeak a likelihood of fault upon the part of a defendant, the law, for civil purposes, permits a jury to infer negligence even though the precise respect in which there was fault cannot be identified. So here, if the suit were for damages, it could be urged (we of course have no occasion here to pass upon it) that the total picture breathes the probability that defendant was careless somewhere and that his unidentifiable carelessness brought about these deaths. And in that connection, we would not be troubled by the possibility that one of defendant’s nurses may have been the careless actor, since for the purposes of civil liability, defendant, as the employer of a nurse, must answer for her fault even though he was personally blameless.
But a criminal case is another matter. The injury to be vindicated is not the personal wrong suffered by the victim but rather an outrage to the State. And the question is not whether a defendant should absorb the dollar loss of his victim but whether his conduct justifies stamping him a criminal and sending him to State Prison. In that inquiry, the test is not ordinary negligence—behavior of which men of [26]*26the highest character are capable. Rather, as phrased in 1 Warren, Homicide (perm. ed. 1938), § 86. p. 424:
“Negligence, to be criminal, must be reckless and wanton and of sucb character as shows an utter disregard for the safety of others under circumstances likely to cause death.”
See State v. Williams, 29 N. J. 27, 40 (1959); State v. Blaine, 104 N. J. L. 325, 327-328 (E. & A. 1928). And whereas a doctor is chargeable in a private suit for the negligence of his mirse-employee, he is not chargeable criminally on the basis of respondeat superior. 1 Burdick, Law of Crimes § 179, p. 231; see State v. Pinto, 129 N. J. L. 255, 257 (Sup. Ct. 1942); State v. Waxman, 93 N. J. L. 27 (Sup. Ct. 1919). “Eor it is of the very essence of our deep-rooted notions of criminal liability that guilt be personal and individual * * *” Sayre, “Criminal Responsibility for Acts of Another,” 43 Harv. L. Rev. 689, 717 (1930). Accordingly, if defendant is to be criminally liable with respect to an act or omission of his nurse, it could not be merely because he was her employer. He could be so liable only if he directed her conduct or assented to it or failed to act with respect to it in circumstances which indicate the same wantonness or recklessness to which we have referred. And finally, whereas in civil matters the plaintiff need prove his case only by a mere preponderance of the proof, yet in a prosecution for manslaughter based upon criminal negligence the State must prove guilt beyond a reasonable doubt, a test which, despite some theoretical devaluations of it, does serve to tell the trier of the facts that a criminal trial is no guessing game.
II.
The proof upon the issue of criminal fault revolved about defendant’s procedures relating to injections and infusions. To anesthetize the patient, defendant injected either amobar-bital or surital into the vein, using the familiar syringe and needle. The infusions were of two kinds. One was of saline [27]*27solution, used immediately after an injection of a drug if the drug was found to irritate the vein. The other solution was a dilute mixture of surital and saline, used to maintain a state of anesthesia first achieved by injection of the drug.
The infusion procedure was the same in both eases. To the bottle containing the solution there was attached a plastic tube of some six feet in length, called a Yen-O-Pak. At the other end of the tube was an adapter designed for attachment to the needle after the syringe was detached from it. The adapter came covered with a removable tip to keep it sterile. Before the infusion was begun, the sterile tip was removed and the solution permitted to run through the tube to clear it of air. If this was done by a nurse employed by defendant, the adapter was recapped with the sterile tip, to be removed by defendant when he connected the adapter to the needle. The bottle was hung in a position well above the patient so that the solution could flow by gravity into the vein.
The actual injection and infusion were done by the defendant and not by a nurse. The infusion was preceded by an injection of the drug into the vein, in which process some blood would enter the needle. When the Yen-O-Pak was attached to the needle, some blood was permitted to enter the adapter to indicate that the needle was still in the vein. Thus in every case the needle and the adapter end of the Yen-O-Pak necessarily became contaminated with the patient’s blood.
With this description we can relate the sundry theories in the State’s case as to how hepatitis, probably brought into defendant’s office by some patient, was transmitted' into the veins of the 40 alleged victims. We emphasize that there was no direct testimony as to what transpired between defendant and the deceased patients. The State relied primarily upon defendant’s records, voluntarily made available to representatives of the State Department of Health, which disclosed treatments of the deceased in which a drug was injected intravenously. Infusions of saline solution were not noted, defendant testifying that they were used only to relieve the vein from drug irritation and that he did not deem them to be [28]*28part of his treatment. The State sought to prove that the alleged criminal neglects were matters of general habit or practice, to the end that the jury could infer that defendant subjected each deceased to them.
We will now list the alleged breaches of proper practice all of which the State contended were of criminal proportions, and we will incidentally comment upon the state of some of the proof in the hope that there will be a fuller presentation upon the retrial we feel obliged to order.
(1) Admittedly the 1000 cc. bottles of saline solution and like bottles of surital solution were used on more than one patient. The average infusion ran between 100 cc. and 200 cc. The State contended that although the blood of a patient would enter only the terminal part of the Ven-O-Pak, nonetheless the virus could in some way travel up six feet of tubing and contaminate the contents of the bottle.
There was no testimony as to whether such multiple use of bottles had ever been found to be a medium of communication of this or any disease. Rather the testimony stressed what a particular hospital or an individual doctor did or did not do, which testimony the defense met in kind. It may be that, if fully explored, the practices were less divergent than a mere statement of them would suggest. Some of the testimony was consistent with the thought that where a patient was being treated for a viral hepatitis, everything used upon him was discarded because so little was known about the behavior of the virus. Or it may be that the unused portion of a bottle of an intravenous solution was discarded because what remained was too little for use upon another patient and the economics involved did not justify retaining the unused portion. What impresses us is the categorical testimony of a defense anesthesiologist that multiple use of bottles of anesthetizing solutions administered intravenously was and remains standard practice in surgery.
It seems to us that there need not be so much dispute upon a matter so commonplace, and that there would not be if the testimony were directed to the underlying issue. The testi[29]*29mony should reveal (a) whether the communication of hepatitis by multiple use of bottles of solutions has been demonstrated or is merely feared as a probability or possibility, and if so why; (b) whether the profession generally has been alerted to the alleged danger, to the end that a jury can decide whether defendant knew of it or his ignorance was chargeable to a neglect criminal in nature. As to the second facet, we note that when the State’s expert, Dr. Dougherty, the director of the Division of Preventable Diseases of the New Jersey State Department of Health, testified concerning his review with defendant of his procedures, he did not say that multiple use of bottles offended a known established criterion, but rather he said merely that “This multiple use of bottles was a serious problem in my mind.” Later, in response to the prosecutor’s question, “Well, would you use the same bottle on different patients?” he answered “Ho, sir.” That kind of testimony seems to us to be unnecessarily fuzzy. It should be sharpened to reveal what the profession knew and how widespread that knowledge was at the time of defendant’s treatment of the deceased.
We have commented upon the state of the evidence for the purpose of guidance at retrial. So far as the present appeal is concerned, the pertinent fact is that the State’s contention that multiple use of these bottles constituted criminal negligence was one of the theses before the jury. We add that the State did not prove that the decedents were in fact subjected to an infusion from a bottle that had been used on a patient who already had the disease.
(2) Hext the State contended defendant used the same Ven-O-Pak on more than one patient. It will be recalled the Yen-O-Pak is the tube which conducted the fluid from the bottle to the needle. The tube being plastic, it could not be sterilized for re-use. The defense agreed that a tube must not be re-used because the blood of the first patient would contaminate the adapter and use upon another patient would involve an unnecessary risk of infection. In short, as to this, there was no dispute upon the topic of prudent practice. [30]*30Rather the question was whether Ven-O-Paks were re-used. The State offered testimony of former patients or members of their families, most of which was intended circumstantially to indicate such re-use. Defendant and his three nurses (one his wife), all of whom are registered nurses, strongly denied any such thing occurred. In this connection the records of the defendant revealed that during the period here involved, January 1, 1960 to October 25, 1960 when defendant ceased to administer intravenously pursuant to an order of the State Department of Health, he had used 116 bottles of 1,000 cc. and 27 bottles of 250 cc. whereas during that same period 918 Ven-O-Paks were used, 27 with the smaller bottles which bottles were not re-used, leaving 891 Ven-O-Paks which were used with the 116 of the larger bottles for an average of 7.6 Ven-O-Paks per bottle. Those figures, if true, would quite effectively destroy the State’s thesis as to Ven-O-Paks since they negate the idea that one Ven-O-Pak was used for each 1,000 cc. bottle. The average of 7.6 per bottle squares with the testimony that the average infusion ran somewhere between 100 cc. and 200 cc. We add that the State did not dispute, at least testimonially, the records concerning purchases or the inventory count which figures in the computation and which was made jointly with a representative of the State Department of Health.
Again, as in the case of the bottles of solution, the State did not prove that the decedents received an infusion after the tubing had been used upon a patient who already had the disease.
(3) Another thesis was that the sterilization procedure was inadequate. Defendant used a dry-heat sterilizer, a product which the record indicates to be standard equipment, reputably manufactured and sold. The syringes and needles, after being immersed in a chemical solution for some period and then rinsed, were placed in the sterilizer which was set for 375° E. and were treated for 15 minutes after that temperature was reached. Sterilization is the immediate task and responsibility of the registered nurse who, according to de[31]*31fense testimony, is trained in that area. This is not to say that a physician has no responsibility to ascertain the sufficiency of the procedures in his office, but rather that the nurse too is apparently expert.
As to this critical aspect of the case, the evidence seems to lack the depth we would think could readily be reached. In the State’s case Dr. Popper testified that in his treatise on the liver, published in 1957, he included a short paragraph on the sterilization required with respect to the virus of hepatitis, the contents of which were “taken from the literature, not taken from my own experience.” That text recommends auto-claving (a steam process) for 20 minutes at 15 pounds pressure at 121 degrees, boiling in water for at least 10 minutes, or “dry heat at 180 degrees for one hour.” Dr. Popper testified he was speaking of centigrade and not Fahrenheit. Translated into Fahrenheit, 180 degrees would equal 356 degrees. Thus an apparent conflict exists between 356° F. for one hour which Dr. Popper had gathered from literature he examined, and 375° F. for 15 minutes which defendant’s nurses used.
Defendant and his wife both testified that the figures they followed complied with the directions given by the manufacturer’s distributor when they bought the sterilizer. Mrs. Weiner also testified that they coincided with what she had done elsewhere as a registered nurse. Curiously, although the State called the salesman of the distributor to prove the date when defendant purchased an autoclave and the defense brought out from him the standard nature of the dry-heat sterilizer, yet neither side explored the question of manufacturer’s instructions as to proper use. We are puzzled, too, as to why the State’s witnesses, who are specialists in public health, were not interrogated upon a subject of such obvious significance in the search for the cause of this tragic experience. We should think that authoritative information ought to be available in literature directly connected with the topic of sterilization, and that physicians selecting a sterilization technique would hardly search for an isolated statement in a [32]*32book devoted to so specialized a subject as the problems of a single organ of the body. We gather from the testimony that sterilization is taught in nursing schools and in medical schools. If so, there should be available testimony as to what the nursing and medical professions are trained to do.
Again, our comments are for the retrial. Eor present purposes the pertinent fact is that the jury had before it a disputed claim as to adequacy of the sterilization procedure.
(4) Another possible source was the drug bottle. One former patient testified that on a single occasion defendant, after injecting the needle into her vein, withdrew it, ejected the contents into the sink, and then put the contaminated needle into the drug bottle to refill the syringe. Defendant denied that occurred. The witness did not indicate the size of the drug bottle. Her testimony of course could not establish a habit, but that fact is really of no moment. Its significance on the overall scene is the suggestion that drug bottles could have been the vehicle for dissemination of contaminated material. If, for example, a needle had not been effectively sterilized either because the technique itself was inadequate or because a nurse had failed to follow the established procedures, or a nurse or the defendant had unwittingly contaminated a needle after it was sterilized, the insertion of such a needle into the drug bottle could presumably contaminate the entire contents. In this connection we note that so far as we can find in the testimony, this possible route for spreading the virus seems significant only with respect to surital. As to that drug, the nurses prepared a solution of 200 cc. from which 8 cc. were withdrawn per injection so that a maximum of 25 injections could be made from a single bottle. Some of that solution was also used to prepare a less concentrated solution in 1000 cc. bottles, each of which was used for infusions for an average of seven patients.
(5) There were still other matters referred to in the testimony. The syringes were filled by the nurses and placed in alcohol pads to maintain sterility until defendant was ready to use them. That practice as such was not challenged but the [33]*33State did question the length of time which elapsed between preparation and use. At argument, we inquired from the prosecutor whether this was another avenue for the spread of hepatitis, to which he replied that he did not so contend. If that be so, then of course the proof did not belong in the case at all. What the jury understood, we cannot know. Eurther, there was testimony that on occasions blood was found on furnishings such as a couch. Again we cannot tell whether the State contended, or the jury understood the State contended, that defendant was criminally culpable in that regard and that the spread of the disease was attributable to it.
Another phase of the issue of criminal responsibility is whether defendant was indifferent to warning signs that a viral hepatitis was being transmitted in his practice. In this connection the pattern of the onset of the illnesses is significant.
One patient apparently revealed jaundice on January 15, 1960, and two patients showed jaundice in May. As to them, Dr. Dougherty testified for the State that they “may have been a chance occurrence” which we take to mean that these illnesses could not be said to have been acquired from defendant’s practice. Seven patients became ill in July, the illness being fatal as to three. Defendant was acquitted as to two of the three, presumably because the jury found the cause of death was not hepatitis. Defendant testified that when evidence of jaundice appeared in these early eases, his assumption was that the patients had toxic hepatitis caused by certain drugs he prescribed for them, which drugs were known to be hepatotoxic, i. e., capable of causing toxic hepatitis in a limited percentage of users. He testified he took the patients off those drugs and treated them for toxic hepatitis, that he obtained satisfactory results in most cases, and that in the instances in which he did not, he returned the patients to the doctors who had referred them.
A patient became ill on each of the following dates: August 14, September 3, 7, 16 and 21. Of the patients already mentioned, one died on September V, another September 15, [34]*34and another on September 24. Defendant had discussed the cases with other doctors and on September 24, one of them, Dr. Bond, made the first suggestion that these might not be cases of toxic hepatitis. Dr. Bond then recommended that defendant switch to the autoclave instead of dry-heat sterilization and use disposable material whenever possible. Thereupon defendant used only disposable needles and 250 cc. bottles of saline solution so that upon completion of an infusion the needle, tube and bottle were thrown away. The autoclave was purchased and put in use on September 29.
On October 18, by which time additional illnesses had appeared and two more had died, defendant, who had earlier been in touch with the local health officer, telephoned Dr. Dougherty of the State Department of Health and informed him that there was hepatitis in his practice. On October 24 defendant met with Dr. Dougherty, who meanwhile had received word from Pennsylvania of two or three deaths to which we have already referred. On the following day the State Department of Health ordered defendant to cease administering intravenous injections or infusions.
In summary, as one epidemiologist testified, there were two “waves” of the disease. The first was the smaller group in July. The second was the massive outbreak in September, October and November. This pattern may not be too revealing as to when the disease was transmitted. It will be recalled that the period of incubation is six weeks to six months or more, so that the epidemic could be due to some breakdown in defendant’s office for a limited period of time or it could be due to some continuous cause or causes.
III.
With the foregoing in view, we can turn to defendant’s complaint that the trial court erred in refusing his motion for a separate trial of each criminal charge. The motion was addressed to the sound discretion of the trial court. State v. Manney, 26 N. J. 362 (1958). The objective of a com[35]*35mon trial is economy and efficiency for both the prosecution and the defense; the important proviso is that there shall not be prejudice to a defendant’s right to a fair trial either by reason of confusion of issues or proof or by reason of a likelihood that multiple charges will prove each other or prove themselves through the sheer weight of numbers.
It seems to us that here the issue does not turn upon the conventional question whether the jury could keep the proofs separate and decide each charge only upon the proof which relates to it. We say this because the State would have to offer the very same proof if but a single count were tried, and if that offer would be proper, as we think it would, then the fact that many charges are being tried together is of no real moment.
The State would have to offer the same proof on the trial of a single count for several reasons. As we have already noted, there was no way to prove that any of the deaths was due to serum hepatitis other than by showing the entire scene and drawing the epidemiological inference it would permit. Hence without the proof that a large number of patients were allegedly infected, the State’s ease would fall. Further, the State was unable to prove precisely what happened between defendant and any decedent and hence had to rely upon proof of habitual practices, to the end that the jury might infer that the same practices were followed in the treatment of the deceased. Hence, realistically the question is not whether there should be 15 trials but whether there may be none at all.
No one who has been on the firing line would minimize the difficulty of defending this doctor against the backdrop of the total tragedy. The single fact of 40 alleged victims, with 15 dead, could readily reverse the presumption of innocence and cast upon defendant the heavy task of proving himself guiltless. Nonetheless, since the alternative is no trial at all, we think the State must be permitted to present its case in the only way that these most unusual circumstances will permit, even though a disclosure of the [36]*36dimensions of the misfortune could obfuscate the true issues. But this very hazard and the odds with which it confronts the accused, make it imperative that the courts be meticulous in their demand that the issues be laid out before the jury clearly and sharply, for without such guidance the risk is too great that the verdict will be a response to the tragedy alone and nothing more.
IV.
The issue which we think was not adequately dealt with is causation. At the close of the State’s case the defendant moved for judgment on the ground that, if it is assumed the decedents died of serum hepatitis, still the State had not proved their deaths were causally related to a criminal failure on the part of the defendant. It will be recalled that the State advanced at least four primary theses of how the serum hepatitis was transmitted, but the State could not prove that any one of those possibilities was in fact the culpable one. The reason, as we have already noted, is that the virus cannot be isolated and hence the infection could not be traced to any of the alleged breaches by defendant of good medical practice.
In fact the State did not attempt to prove causal connection in the conventional way, by expert testimony addressed to that issue. Rather it concentrated its expert testimony upon the question whether the hepatitis was serum rather than infectious or toxic. The State did not ask these witnesses to point to the act or omission of defendant which was the probable cause of the transmission of the disease or to those acts or omissions which together constituted the likely vehicles of that transmission. The witnesses touched the area but incidentally and without this problem in focus. Thus Dr. Dougherty, in explaining why he concluded the deaths were due to serum hepatitis, referred to so much of the hypothetical question as included the testimony concerning re-use of Ven-O-Paks and the testi[37]*37mony that on one occasion after the needle had entered the witness’s vein and some blood been withdrawn into the syringe, defendant expelled the contents and re-entered the bottle of medication to refill the syringe. These incidents were described by Dr. Dougherty as involving “a risk of exposure to blood and its products.” It may be noted that he made no reference to multiple use of bottles of saline solution or surital-saline solution, nor to the dry-heat sterilizer as used by defendant and his nurses. In fact the hypothetical question made no reference to the sterilization procedure. Dr. Joseph Stokes, Jr., in giving the reasons for his opinion that the deaths were caused by serum hepatitis, referred only to so much of the hypothetical question as revealed “that multiple injections were made from the same bottle; that there were indications of contamination of the tubing.” We assume “injections” referred to drugs and hence to contamination of the drug bottles rather than to contamination of the infusion solutions in the bottles. And finally, Dr. W. Paul Havens, in stating why he believed the deaths were due to serum hepatitis, noted that the hypothetical question includes “the history of reception of material that was potentially contaminated,” which led to the following question by the prosecutor and answer:
“Q. Doctor, what part of the equipment do you consider to have been contaminated or potentially contaminated?
A. Well, if I interpret correctly the facts in the hypothetical question, it would appear to me that a great many things were potentially contaminated.
The technique as described herein certainly would provide numerous opportunities for contamination not only of tubing, not only of the adapters, of the needles, syringes, furnishings of the office, I would think, since I gather that blood did appear in various places outside of the body.”
Thus the State did not try by expert proof to establish a causal connection between the deaths and any specific act or omission. Nor did the State seek by such testimony to identify all the acts or omissions which constitute the likely vehicles or avenues of transmitting the disease. We can but [38]*38infer what acts or omissions the State had in mind, and as to this we listed above four such matters and then added a fifth category which the jury may or may not have thought to be pertinent.
If the State had tried this ease upon the sole thesis that defendant had subjected the decedents to Ven-O-Pak tubings contaminated with the blood of other patients, the issue of causation would not realistically present any difficulty. The reason is that multiple use of the tubings would so likely spread the disease that, if one found the tubings were so re-used regularly, he would look no further. But the State did not try the case upon that single theme, and for all we can know, the jury may have found for defendant upon that charge. Rather the State advanced the sundry additional theses we described above. It is as to them that we think the problem of causation was not adequately handled.
With respect to such other theses of criminal fault, we could not see how the jury could find from the evidence which of those possible mediums of transmission of the disease (i. e., improper sterilization, multiple use of saline bottles, contamination of drugs) was in fact the medium, and upon the reargument we ordered, we understood the State to agree with our view. If there is no way to infer that any one of the mentioned mediums for the transmission of the disease did in fact transmit it to the decedents, then it would not be enough for the jury to find defendant was criminally negligent as to but one of the possible mediums the jury found to be established by the proof. Rather, to convict, the jury would have to find defendant was criminally negligent as to all of the established mediums, for in no other way could it be said that it was his criminal negligence which caused death. We invited attention to that specific proposition in connection with the reargument. We propounded the question whether, if the jury could not find which of the possible mediums was in fact the medium,
“* * * then should the jury have been instructed that tbe defendant must be acquitted unless the jury found that defendant was [39]*39criminally culpable with respect to all of these mediums [of transmission of the disease]?”
In reply the State insisted that a conviction would be proper if the jury found criminal negligence as to any one of the vehicles of transmitting the disease. The State argued, by analogy, that if a man were charged with causing death of a pedestrian by criminal negligence in driving a car (a) while drunk, (b) at 70 miles an hour in a 25-mile zone, (c) through a red light, and (d) onto a crosswalk teeming with people, the jury could convict without finding defendant did all of those things. That may be so, but the analogy fails because in the hypothetical case the jury could conclude that the reckless act it found did in fact cause the death. In the ease before us, it would not be enough to find, for example, that defendant was criminally negligent with respect to multiple use of bottles of solution, because, as the State concedes, there is just no way to say that that act transmitted the virus and brought about the deaths with which defendant is charged. Eor all that one could tell, the fatal failure, according to the State’s own thesis, could have been in the sterilization of needles and syringes, as to which the jury, although accepting the State’s claim that the procedure was inadequate, may have found defendant was not negligent or was not criminally negligent. Hence the deaths cannot be attributed criminally to defendant unless he is found to have been criminally culpable as to all the mediums which could have transmitted the virus, i. e., all the mediums projected by the State except such of them as the jury should find the evidence did not establish.
At a retrial, the State should by expert proof direct attention to the acts or omissions which are the probable vehicles for transmitting the disease. In that way defendant will know what to meet and a jury will know the area in which criminal negligence must be found. If the state of medical knowledge does not permit such delineation, that fact should be disclosed to the end that the adequacy of the proof can [40]*40be weighed by the court and jury in the discharge of their respective duties.
We add that the trial court should have instructed the jury with respect to defendant’s criminal liability for the negligence of his staff. The defense requested instructions upon that topic which, however, were not granted. The trial court mentioned the subject only with respect to Yen-O-Paks, as to which it said:
“The evidence indicated that it was the duty of the nurses employed by the defendant to change the Ven-O-Pak or tube after each infusion. If you conclude from the evidence that the nurses failed to perform this function contrary to the rules of their employment, and you are convinced beyond a reasonable doubt that this fact was known or should have been hnown to the accused, and the failure to do so was a proximate cause of the death of anyone or all of the 15 decedents, then you would be justified in finding the defendant guilty of any or all of the counts of the indictment.” (Emphasis added)
The jury returned 40 minutes later with a request of which only the following is revealed:
“In your Honor’s charge, specific reference was made regarding a doctor’s responsibility and/or liability for over [overt?] acts of commission or omission by nurses in his employ which are the proximate cause of some subsequent wrong.”
We do not know what the jury’s question was, since the trial court read into the record only the foregoing portion of the jury’s communication. The trial court responded, “I am going to read to you that particular paragraph I feel you have reference to, since you refer to my charge.”' The trial court then repeated the portion of the charge we quoted above, whereupon the defense objected to the charge as to its substantive content and iterated its objection to the court’s failure to charge the requests the defense had submitted.
The difficulty with the instruction as given is that it makes defendant culpable with respect to a nurse’s failure to perform her duty if her failure “should have been known” to him. As we have said, defendant could be liable with respect [41]*41to a nurse’s act ox omission only if he was personally culpable, that is, if he authorized or assented to it or himself was guilty of wanton and reckless indifference with respect to it. It so happens that as to the Ven-O-Paks, the use of “should have been Imown to the accused” was of no possible harm, since it is clear that defendant had to know of a nurse’s failure because only he attached the adapter to the needle and in that process he would necessarily know whether the Ven-O-Pak had been used. Nonetheless, while the instruction was harmless as to Ven-O-Paks, there would be no reason apparent to the jury why defendant would not also be criminally liable if some other failure of a nurse (as to sterilization for example) “should have been known” to him. Thus, under the facts of this case, the standard of responsibility, laid down as to a nurse’s handling of Ven-O-Paks, would likely be understood by the jury to pervade the entire case and to warrant a conviction even though defendant’s failure to know of his nurse’s act or omission was not a failure of criminal proportions.
If the jury understood the charge related only to Ven-O-Paks, then the jury was wholly uninstmcted upon the question of defendant’s responsibility with respect to other acts or omissions of his nurses. As we have said, defendant requested charges upon that subject. The jury’s inquiry was not in terms limited to Ven-O-Paks; it spoke of “overt acts of commission or omission by nurses in his employ.” The jury should have been suitably instructed, especially since most laymen probably know an employer is civilly liable for his employee’s conduct and hence might assume the same or a similar rule applies in criminal matters. We know the jury was interested in the subject, and since the proof could well leave the jury in doubt as to whether a nurse was the one who failed, the jury should have been told what is required to inculpate defendant with respect to such failure.
The judgments of conviction are reversed and the matters remanded for new trial.