Pathogenesis 615 



germicides, and is also destroyed by acids. Hashimoto* found that 

 it could not live longer than fifteen minutes in vinegar containing 

 2.2-3.2 per cent, of acetic acid. 



According to Frankel, the organisms in the liquefied cultures all 

 die in eight weeks, and cannot be transplanted. Kitasato, how- 

 ever, has found them living and active on agar-agar after from 

 ten to thirty days, and Koch occasionally found some alive after 

 two years. 



This low vital resistance of the microbe is very fortunate, for 

 it enables us to establish satisfactory precautions, for the prevention 

 of the spread of the disease. Excreta, soiled clothing, etc., are 

 readily rendered harmless by the proper use of disinfectants. Water 

 and food are rendered innocuous by boiling or cooking. Vessels 

 may be disinfected by thorough washing with jets of boiling water 

 discharged through a hose connected with a boiler, and baggage 

 can be sterilized by superheated steam. 



Metabolic Products.- — ^Indol is one of the characteristic metaboUc 

 products of the cholera spirillum. All that is necessary to demon- 

 strate its presence in a colorless solution is to add a drop or two of 

 chemically pure sulphuric acid, when the well-known reddish color 

 will appear. 



This reaction depends upon the fact that the organism produces 

 nitrites, so that their addition is not necessary to bring out the red 

 color. On this account, the product is known as nitroso-indol. 



The organism also produces acid in milk and other media. Bitter 

 has also shown that the cholera organism produces a peptonizing 

 and probably also a diastatic ferment. 



Toxic Products.- — Rietsch thinks . the intestinal changes depend 

 upon the action of the peptonizing ferment. Cantani, Nicati and 

 Rietsch, Van Ermengem, Klebs, and others found toxic effects 

 from cultures administered to dogs and other animals. Several 

 toxic metaboUc products of the spirilla have been isolated. Brieger, f 

 Brieger and Frankel,J Gamaleia,§ Sobernheim,|| and Villiers have 

 studied more or less similar toxic products. The real toxic substance 

 is, however, not known. 



Pathogenesis. — ^Through what activity the cholera organism 

 provokes its pathogenic action is not yet determined. The organ- 

 isms, however, abound in the intestinal contents, penetrate spar- 

 ingly into the tissues, but slightly invade the lymphatics, and 

 almost never enter the circulation; hence it is but natural to conclude 

 that the first action must be an irritative one depending upon toxin- 

 formation in the intestine. 



In the beginning of the disease the small and large intestines 



* "Kwai Med. Jour.," Tokyo, 1893. 



t "Berliner klin. Wochenschrift," 1887, p. 817. 



t "Untersuchungen uber die Bakteriengifte," etc., Berlin, 1890. 



§ "Archiv de mfid. exp.," iv, No. 2. 



II "Zeitschrift fUr Hygiene," 1893, xrv, 145. 



