TEXT-BOOK OF BACTERIOLOGY. 275 



or rice-water, frequent vomiting, complete loss of appetite, and vio- 

 lent thirst belong to this group. All this can readily be explained 

 as an immediate consequence of the effects of bacteria. 



There will also be regularly noticed the sj'mptoms of severe 

 general suffering, increasing weakness of the heart, terminating 

 in a complete stoppage of the circulation, lowering of temperature, 

 superficial respiration, and spasms of the muscles; all these 

 suggest that other regions are likewise affected. Micro-organ- 

 isms appear, however, only in the intestine, never in the blood or 

 the internal organs, and a direct connection cannot be estab- 

 lished. Koch thinks that the bacteria produce an active poison in 

 the intestine while developing, and that this poison is taken up by 

 the lymphatics or blood-current and distributed all over the body. 

 Such toxically active substances have, in fact, become known as 

 direct products of the metabolism of the comma bacilli, and these 

 appear, together with basic bodies, to exist as peculiar albuminous 

 substances of the class of toxalbumins and play an essential part in 

 the disease. 



The post-mortem changes are almost wholly confined to the in- 

 testine. The duodenum is more or less filled with a watery, color- 

 less fluid, frequently, however, possessing a somewhat firmer quality 

 and resembling gruel. The intestinal mucous membrane is swollen 

 and reddened, most noticeably in the region above Bauhin's valve; 

 but the reddening and swelling is often restricted to the borders of 

 the lymph- follicles and Peyer's patches. 



Here the bacteria are found to have entered the substance of 

 the intestinal wall. 



We stain sections for twenty-four hours in common fuchsin or 

 in alkaline methyl-blue solution. The bacteria are decolored ac- 

 cording to Gram. In successful preparations the micro-organisms 

 are seen in the tubular glands, and it will also be seen that they 

 have penetrated in part between the basement membrane and 

 the epitheliurii and forced the latter from its foundation. The bac- 

 teria have also their characteristic comma figure in the tissue and 

 lie close together in dense heaps. 



The examination of other organs is practically negative. 



One more point in conclusion might be briefiy mentioned — i.e., 

 the question whether by overcoming cholera once we are protected 

 against a renewed attack of the disease. A sort of immunity seems, 

 in fact, to take place, though it is not of any considerable duration. 

 It is an extremely rare occurrence to find any one afflicted twice in 

 the course of the same epidemic, but this diminished susceptibility 

 does not generally last more than about four or five years. 



