DIARRHEAL DISEASES. 135 



these there are some which possess a violently poisonous 

 nature. Such toxic products are developed in laboratory 

 experiments when putrefactive bacteria act upon albuminoid 

 materials, and it must be inferred that similar products 

 arise in the intestines under similar conditions. The con- 

 clusion that digestive derangements are, in part, due to the 

 absorption of such toxic products is extremely probable. 

 It is suggestive to notice that Fliigge (192) has proved that 

 there exist in milk, after the lactic bacteria have been killed 

 by heat, certain species of microorganisms that develop 

 toxic products, to which he attributes some of the digestive 

 derangements caused by milk. Some of these bacteria 

 belong to the putrefactive class. 



At the present time, however, the data in our possession 

 are quite insufficient to enable us to state with positiveness 

 whether these putrefactive bacteria are primary or only 

 secondary agents in connection with the intestinal disturb- 

 ances. It is quite certain then that the presence of large 

 numbers of putrefactive bacteria in the milk must be looked 

 upon as extremely undesirable, and as, in all probability, 

 rendering the milk unwholesome. Such milk would cer- 

 tainly be likely to produce digestive disturbances; but 

 whether any of the numerous forms of intestinal troubles 

 are directly attributable to the putrefactive organisms can- 

 not be positively stated. 



The growth of bacteria in normal milk is somewhat sug- 

 gestive in this connection. As already pointed out the lactic 

 bacteria ordinarily soon obtain a mastery over and pre- 

 vent the growth of the putrefactive forms. As the lactic 

 bacteria become more abundant the liquefying species grad- 

 ually become less numerous, and finally seem to disappear. 

 As a result the milk that is on the verge of souring ordina- 

 rily contains none of these putrefactive bacteria. But, occa- 

 sionally, quite a different result is found. Sometimes, for 



