Contemporaneously with and partly preceding the bacteriologic era came the work of von Ritter, Klebs, Epstein, Czerny-Moser, R. Fischl, Hutinel, with their pupils, with whose work is associated on the ground of further hospital observations that of Finkelstein, Heubner, Escherich, Blum and others. These writers investigated the special character and peculiar etiology of gastro-enteric cases occurring in foundling homes and infant hospitals, and demonstrated the widely varying course of such. cases from that of summer diarrhcea, the frequent absence of injuries to digestion as causes of disease, and the occurrence of epidemics and infection by contact. The septic character of some of these cases has been mentioned, and I have proposed the term "sepsis with gastro-intestinal symptoms" for cases in which gastro enteric symptoms tire only- clinical appearances occurring in the course of an infection running all entirely different course.
Pasteur's discoveries of the bacterial uncleanliness of our means of nourishment drew attention—already arou.sed by the course of cases of summer diarrhata—to this source of infection. Its significance appears clearly to result from the rapid and enormous increase in the bacterial contents of cow's milk (Miguel, Escherich-Cnopf, 1S90). The ingenious discovery through Soxidet of simple apparatus for the sterilization of milk was received with the most joyful expectations. Nevertheless this method disappointed the hopes raised, its failure being proven by the fact that in the course of twenty years infant mortality was scarcely affected. Thorough researches into the above method of sterilization ailOW what defects are inherent in it, and what dangers it conceals (Fltigge, 1894, Marian, 1900).
The poor results of the artificial rearing of infants with nourish ment sterile in the bacteriologic sense, and the frequency of chronic disturbances of nutrition in children so nourished, suggested that the cause should be sought in the differences in composition and adapta bility of human and animal milk. A number of successive publications reaching to the most recent time follow-ed. They begin with the work of Biedert, Camerer, and Pfeiffer, who pointed the way in a number of researches on the differences in various kinds of milk, and their significance in the infantile inte.stine. Schlossmann, Knopfelmacher, Selter and others confirm the value of these researches, while liculmer, Salge, and Bendix consider theni of no great importance. These re searches cumulate in the publications of Czerny and his pupils (begin ning in 1897) together with those of Bendix, Terrien, and Pfaundler, who cliscovered that the origin of chronic disturbances of nutrition in infancy lay not in insufficient absorption, and in secondary decomposi tion of the food residue, but rather in poisons, especially acids, formed from the food materials, and from faulty function in the course of metabolism.
A further advance in our point of view had as a result the recog nition of enzymes, which have proved to be common to a small extent to all kinds of milk, and to a greater extent specific for each variety, and fitted to the requirement of the particular vaiiety of animal. The interesting researches on this subject, which belong to the last years of the nineteenth and the first years of the present century, are associated with the names of Raudnitz, Marfan, Escherich, Nobecourt, Merklen, Halhan, van de Ve Landtsheer, Moro, Spolverini, and others. Nevertheless we are left with the impression that the significance of enzymes has been much exaggerated, and that their practical value must be but small.
Also the exceedingly significant experimental researches of Paw low and his pupils (published in lecture form 1S08) were very fruitful in connection with the proper understanding of the nature of digestion. Their results were applied by individual authors (Siegert, 1002) to the study and treatment of diseases of nutrition.
The studies of Bordet, Uhlenhuth, Ascoli, and others, on the for mation of precipitin, and through it the recognition of the specificity of various kinds of albuminous bodies, stimulated the recent researches of Wassermann, Hamburger, Schlossmann, Moro, and Finkelstein. These investigators reached the conclusion that the constituents of various kinds of milk were peculiar to the particular milk. This con clusion has helped in the comprehension of certain toxic symptoms, which appear in artificially fed babies, and at the time of weaning, and frequently manifest themselves in the form of SCNTIT gastro-enteric disturbances. Indeed, an immunizing treatment is said to have been already successfully established (Schlossmann, 1905).
At the same time there have been endeavors, through researches on the microscopic anatomy of the intestinal canal, to establish findings corresponding to individual clinical types, although the respective works of Baginsky, R. Fischl, Marfan, Ileubner, Bloch, Tugendreich and others have not resulted in agreement.