SUMMER DIARRHCEAS OF INFANCY. 133 



tion unless they be broken down. The pyogenetic substance 

 contained within the bacterial cell can have no chemotactic 

 action until the cell disintegrates. Thus, the anthrax 

 bacillus contains a pyogenetic substance, but no pus is 

 formed in mice with anthrax, because there is no destruction 

 of the bacilli. This pyogenetic proteid of the anthrax 

 bacillus, however, manifests its action in malignant pustule. 

 These experiments are of the greatest interest. We must 

 say, however, that it is possible that the bacterial cellular 

 proteid may be modified by the treatment to which it has 

 been subjected in these experiments. We do not as yet 

 know enough about the nature of this proteid to say that 

 its nature and its action are not altered by being heated for 

 hours with an alkali. However, accepting Buchner's 

 work, it throws much light upon processes which have 

 heretofore been but imperfectly understood. 



The Summer Diarrhceas or Infancy. — In a paper 

 published in 1888, Vaughan stated that the microorgan- 

 isms which produce the catarrhal or mucous diarrhoeas of 

 infancy are probably only putrefactive or saprophytic in 

 character, and that they prove harmful by splitting up 

 complex molecules and forming chemical poisons. At that 

 time it was generally believed that a specific germ would 

 be found, but the truth of the above statement is being 

 made more manifest with every experimental study of the 

 subject. Able and diligent bacteriologists, among whom 

 Booker, in this country, and Escherich, in Germany, 

 deserve special mention, have made a careful study of the 

 bacteria found in the intestines and stools in these diseases, 

 and all agree that no specific organism has been found. 

 Booker has reported the isolation of more than thirty 

 kinds. In true cholera infantum the proteus group of bac- 

 teria was found in fifteen out of nineteen cases, but in the 

 ordinary diarrhceas there is no constancy in the species 

 present. Germs which are frequently found one year are 

 rarely seen in the cases observed the next summer. This 

 has been the experience of all who have studied the bacteria 

 of the summer diarrhoeas of infancy. Vaughan has studied 



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