96 BACTERIAL POISONS. 



latter in the same medium are inert. Not only are these 

 two organisms morphologically and biologically distinct, 

 but their poisons are chemically unlike. Briegbr and 

 Frank EL precipitated the poisonous albumin of the germ 

 of KiTASATO with alcohol, but this reagent renders the 

 poison of the Italian germ inert. Notwithstanding this 

 difference, however, both microorganisms and their chemical 

 products produce tetanic convulsions and death in the lower 

 animals. We must, therefore, admit that there are at least 

 two distinct germs, each of which is capable of causing 

 tetanus ; and how many other bacteria with like properties 

 there may be no one can tell. All attempts to find a mor- 

 phologically specific germ in the summer diarrhoeas of 

 infancy have failed. The labors of Booker in this coun- 

 try and of EsCHEEiCH in Germany have shown that no 

 one species or variety is constantly present. No less than 

 thirty distinct germs have been obtained from the bowels 

 and feces of children suifering from these diarrhoeas. A 

 germ which is frequently present one season may not be 

 found at all the next. Are we to conclude from this fail- 

 ure to comply with the first of Koch's rules, that the sum- 

 mer diarrhceas of infancy are not due to microorganisms ? 

 Certainly not ; especially in view of the fact that Baginsky 

 and Stadthagen have obtained from pure cultures of a 

 saprophytic germ found in the stools of cholera infantum a 

 poisonous base and a poisonous proteid ; and Vaughan 

 has shown that at least three of Booker's bacteria pro- 

 duce chemical poisons which cause in kittens retching, 

 vomiting, purging, collapse, and death. To the contrary 

 we are justified in concluding that these diarrhoeas may be 

 due to any one or more of a number of germs which difier 

 from one another sufficiently morphologically to be classified 

 as distinct species. The similarity among these bacteria 

 will not be discovered by a study of their size, form, and 

 reactions with staining agents, but by a study of their 

 chemical products, the agents by virtue of which they cause 

 the disease. 



We think that we are justified in concluding that in 

 those diseases in which the four rules of Koch have been 



