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a weakened gastro-intestinal tract as the bacteria themselves. The milk is subjected to a sufficient heat to bring the bacterial count down to about 1,000 or 1,200, and when we have achieved that limit we have found that all the pathogenic germs are destroyed; the milk still contains a sufficient number of lactic ferment bacteria for purposes of disintegration and digestion in the stomach; the lacto-albumens are still uncoagulated, and the caseins are unfixed and ready for assimilation.

If we carry the milk farther along in the pasteurizing process, it becomes practically sterile. The lacto-albumens coagulate and are difficult or even impossible of digestion by a weak stomach, and the only purpose of such a milk will be derived from the whey it contains, with the small amount of proteid, the sterile water, and the considerable quantity of carbo-hydrate or caloric matter that the whey contains. But the very inertness of the mass is sometimes of benefit to the physician where, for temporary periods, the stomach has practically ceased its function.

For some cases the physician will require that the milk, after sterilization, be subjected to a modifying or disintegrating process. At the Michael Reese Hospital we use for this purpose some such rennet ferment as the German Pegnin powder, or preferably a composition put up by Armour & Co. from a formula furnished by the Michael Reese Hospital pediatric staff, and which they call paracasogen. These powders seem to have the effect of completely disintegrating the coagulated albumens and the chemically fixed caseins. and rendering them even more highly available for assimilation than in their original state, without the fermentative and consequently irritating properties of the raw article.

In the long course of experiments which were made before we arrived at our present manipulations in the milk station, we came upon some curious facts. We found, for one thing, that long after the operation of pasteurizing the milk had ceased, and the heat had been withdrawn, the destruction of the lactic acid bacteria went on; for instance, if we had pasteurized the milk down to 1,000 or 1,200, as indicated immediately after the heat had been withdrawn, we found that in six hours, with the milk in the refrigerator at 33 degrees, there were enough more bacteria destroyed to bring the count down to about 100,, and we found that

where the milk was maintained at refrigeration the recovery of these bacteria from the shock of pasteurizing was so slow that the count remained practically stationary for twelve or even twenty-four hours. We found also that the higher the pasteurization the more difficult it was of digestion for weakened infantile stomachs. In other words, we found that where a sterilized milk would not digest at all a milk of say a count of 100 or 200 was only slightly digestible, and the maximum digestibility of the milk was reached at a pasteurization of about 1,000 or 1,200; a lower pasteurization than that left the milk enough bacteria to become an irritant.

We found that wherever milk was intended for weak stomachs it was first necessary to withdraw all the cream in order to avoid the formation of fatty acids, to which our pediatric staff attribute a large proportion of the gastrointestinal disorders in children that have been overfed.

In the Michael Reese Hospital we are using large quantities of buttermilk, mainly for the same reasons that we sometimes use modified milk-first, to get rid of the fatty acids; second, to give the delicate stomach the benefit of the easily digested whey; and third, to get the benefit of the lacto-albumens and the caseins, which in the fermentative processes of making buttermilk seem to be chemically changed, so that they are almost immediately available for assimilation. The buttermilk we use is made in the institution by means of one of the commercial ferments, and in the usual way.

Notwithstanding the utmost care, both on the part of the physician and the operators of the milk station, it is a daily occurrence to find that the most dainty modification one can make will not be tolerated by some infant stomach that will subsequently take and assimilate a practically unmodified milk; so that the milk station of a hospital is not only a place where scientific methods may be carried out, but where one must of necessity be groping continually in the realm. of experimentation.

If all of our plans and procedures are bent upon the perfection of our milk supply and its proper employment in the hospital, it must not be understood that we can rely wholly upon cow's milk to tide our sick babies over digestive illnesses. We have in our own institution a fairly well organ

ized wet nursing department, and we keep under control a sufficient number of wet nurses to have recourse to their milk when other means fail. The fact that we have a large maternity service perhaps materially aids us in the maintenance of a mother's milk section of the hospital.

REPORT OF MILK TREATMENT.

"I am submitting you herewith a report of a twelve day test of the pasteurization plant of the milk station of Michael Reese Hospital, the test running from May 8th to May 19th, 1908, inclusive. The obect of this test was to determine exactly the efficiency of the plant, to examine carefully the methods and processes employed in handling the milk, and to report the same with any suggestions regarding modifications which would tend to improve that important department of the hospital. With this aim in view samples of the Raw Milk, Filtered Milk, Pasteurized Milk and Pasteurized Milk of twenty-four hours' standing were taken and subected to bacteriological analysis in duplicate obtaining the bacterial content of the inilks and from this data computing the efficiency of pasteurization and of the whole plant. As a presumptive test of the acid forming bacteria usually present in the milk, namely the Lactic Acid bacillus and the Colon bacillus, Litmus Lactose Agar plates were made of the above milk, the number of acid formers found and the effect of pasteurization upon these forms noted. All the plates were incubated at body temperature, thirty-seven and one-half "C. (371⁄2” C.), the bacterial count being made at the end of 24 hours; also some determinations were made upon the acidity of the milk before and after pasteurization, but as practically no difference was found in their reaction, that item is allowed to pass with this brief mention. The data show that the Raw Milk delivered to the station was on the whole 12 days' test only a fair grade of milk, the bacterial count running from 25800 to 616000 per cubic centimetre, seven samples being below 300,000 and one over 600,000 per cubic centimetre; the high samples also had a large number of acid colonies, and I believe were older milks. Sample No. 11 also had a higher acid reaction than the others and was a poor milk for a milk which should be considerably less than 24 hours old. This high milk, of course, showed a very low content after pasteurization, but the toxic properties of the bacteria would still be in the milk. The milk received at the station was of a low temperature and seemed well devoid of dirt and sediment.

Preliminary to pasteurization and sterilization, the milk was rassed through a sterile absorbent cotton filter, the cotton being laid between cotton gauze; the cotton filter was placed in a strainer and the milk passed directly upon the filter, the object being to

remove dirt and any sediment which is usually suspended in Raw Milk. As I saw the process carried on, I know that scarcely any sediment could be removed, the filters were very thin and the force of the milk poured directly upon the cotton caused the cotton to separate leaving nothing but the gauze to act as the filtering medium, the efficiency of which would, of course, be practically nothing. This could be easily remedied by having a metallic disc to act as a spreader for the milk, thus relieving the cotton from the direct force of the milk in pouring; the filter should have a thicker layer of cotton and you would also have a higher removal of bacteria as well as a better removal of the finer suspended matter in the milk.

After filtration, the milk was put into large enamel ware pitchers for sterilization or for pasteurization, the pitchers having been cleaned the evening previous and covered over with a sterile towel. The pitchers were put uncovered into the sterilizer and the steam turned on; the milk for the "formula milk" was sterilized at 212 degrees F., for 30 minutes, the milk being removed from the sterilizer 30 minutes after the temperature of the milk had reached 212 degrees F. The same procedure was followed with the milk to be pasteurized, the time being 30 minutes and the temperature 168 degrees F. After sterilization and pasteurization the milk was put into bottles which had been previously sterilized by steam, either by pouring directly from the pitcher, as in the case of the pasteurized milk, or poured out into flat pans, from which the bottles were filled as in the case of the "formula milk." This general method is open to a large number of objections; you can say, that the less the milk is handled and exposed to the air after sterilization, the less the chances of contamination and the safer the milk. The sterilization of milk in bulk in a large uncovered vessel is decidedly objectionable; (1) The condensation water from the steam condensing on the roof of the sterilizer with any adherent substances, that may be in contact with that surface can and does fall into the milk; this of course is undisable; (2) The accidental contamination of one vessel either in the sterilizer or in the refrigerator would mean the contamination of milk in all the bottles poured from that vessel. To obviate these, would suggest that, if possible, you sterilize the milk in the bottles and do away with the handling of the milk after pasteurization. If this is not possible, and the milk must be pasteurized in bulk, then provide metallic containers that can be plugged with cotton and capped with a cover. This is true of the milk kept in the refrigerator as well as that put into the sterilizer; to prevent contamination the milk should be in a vessel plugged with cotton.

Regarding the time of pasteurization and sterilization, I believe the exposure to heat has been too long. To get a temperature of 212 degrees F. for 30 minutes usually took one and one-half hours exposure to the heat in the sterilizer; to obtain a temperature of

168 degrees F. for 30 minutes usually took an hour or more exposure to heat. This is entirely too long an exposure and I believe it affects the general quality of the milk as far as its digestibility is concerned. Many of the samples showed the precipitation of the Lacto-albumen which is precipitated at about 155-160 degrees F. The data show an exceptionally high efficiency of pasteurization, the lowest being 99.29%, and does not vary very much with the contents of the Raw Milk. There is practically entire destruction of the acid forming bacilli, only one sample showing acid formers in the pasteurized milk Sample No. 4; however, o ndifferentiation those were found to be Lactic Acid Bacilli and not the Colon. The low content of the pasteurized milk on 24 hours' standing should be noted, some of the samples running lower after standing 24 hours than immediately after pasteurization; whether this is due to the low temperature of refrigeration, or whether a sample of the sterilized milk was given me, I do not know. This high efficiency I think should be expected from the amount of exposure to the heat the milk undergoes; in my opinion, everything goes to show that it is over-pasteurized. The sterilization, I believe, can be arranged to require less time and exposure and produce an equal efficiency and not modify the condition of the milk to the extent of the present procedure.

There are many minor points in the process of sterilization that I would like to take up with you in a manner admitting of more detail than in a formal report of this kind; however, I believe you can see from the data that the plant as a whole is producing a milk that i sexceptionally free from bacteria.

This twelve-day test I believe a fair and thorough one and represents the plant as it is actually in use.

May 21, 1908.

(Signed) CONRAD JACOBSON, B. S.,

DIET IN THE HOSPITAL.

This is no place, nor is this paper planned, to discuss the science of feeding, the chemical values of food, or the physi-, ological necessities of various diseases in the matter of diet. These are wholly in the realm of medicine. There are a few features of dietetics, however, that very intimately concern the hospital administrator; one of these is furnishing the facilities for the mechanical distribution of food so that any class of patients or any individual patient in any ward or part of the institution may be restricted to any particular diet indicated by his physician. Where there are hundreds of patients to be fed daily, we all know that there is a dis

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