594 GASTRO-INTESTINAL BACTERIOLOGY 



of urinary ethereal sulphates may be a suggestive index, to the acute 

 toxemias characteristic of bacillary dysentery, typhoid, paratyphoid 

 or cholera. Of course, a variety of other bacteria than the few men- 

 tioned specifically may be concerned, either alone or in symbiosis. 

 Thus streptococci alone and streptococci in association with dysentery 

 bacilli may be justly regarded as the etiological agents in their respec- 

 tive syndromes. The important factor, from the viewpoint of this 

 discussion, is to realize that the formation of nitrogenous products 

 from proteins or protein derivatives which are being utilized by 

 various types of intestinal bacteria for energy may be injurious to the 

 host. These substances are of unknown composition for the most 

 part, but beyond doubt they are nitrogenous. Some, as phenols, 

 cresols, or indol are simple in structure and ordinarily harmless, or 

 nearly so, although long-continued absorption may gradually lead to 

 cumulative effects. Others, as beta imidazoleethylamine and other 

 primary amines formed from amino acids may be physiologically 

 active. The unknown poisons of the meat poisoning group and those 

 characteristic of the various bacteria which cause acute infections 

 of intestinal origin are of unknown structure and complexity. 



The other prominent type of abnormal bacterial activity in the 

 alimentary canal the fermentative type is of entirely different 

 origin; the essential factor is either a decomposition of carbohydrates, 

 with the formation of products abnormal for the intestine, or of excess 

 of normal fermentative products. The abnormality may be a simple 

 hyperacidity, as, for example, that caused by an overgrowth of aciduric 

 bacteria when certain sugars, as maltose, fed in too large amounts, 

 lead to an overdevelopment of the aciduric bacteria; or it may be 

 more complex. This happens frequently when there is an overgrowth 

 of Bacillus aerogenes capsulatus, or of members of the Mucosus Cap- 

 sulatus Group. In the latter event the exact nature of the irritative 

 substance is as yet unknown, but it is in all probability not a nitro- 

 genous compound. It is formed from carbohydrates, which contain 

 no nitrogen. The factors leading to an overgrowth of these organisms 

 in the intestinal tract appear to be an excess of carbohydrate and a . 

 lack of normal lactic-acid-forming bacteria. It is a significant fact 

 that diarrheal cases associated with an overgrowth of the gas bacillus 

 even of several years' duration do not exhibit signs or symptoms of 

 toxemia in spite of the protracted illness. 



It is unfortunate that practically none of the bacteria which incite 

 intestinal disturbances or illness produce soluble toxins against wilich 



