PTOMAINES AND TOXALBUMINS. 



151 



anthrax. In a dry condition it has a grayish-white color and gives 

 the reactions of albumins. 



The toxalbumin of the tetanus bacillus is also soluble in Avater. 

 It is best obtained in bouillon cultures containing glucose. 



G. and F. Klemperer (1891) have announced their success in 

 obtaining a toxalbumin from cultures of Micrococcus pneumonia? 

 croupossB ('diplococcus pneumonia?') ; this they propose to call pneu- 

 motoxin. 



Some recent authors prefer the name toxins for the poisonous 

 products of bacterial growth designated by Brieger and others as 

 "toxalbumins." This avoids any definite statement as to their 

 chemical composition, which appears to be still in doubt. The 

 poisonous precipitates obtained from cultures of the tetanus or the 

 diphtheria bacillus give the reactions of an albumin or albumose 

 (Martin), but it is possible that the toxic substance is simply as- 

 sociated with bodies of this class, and that they have not yet been 

 isolated in a pure state. These toxins in some cases are intimately 

 associated with the bacterial cell intracellular toxins and their 

 toxic effects are exhibited when small quantities of dead bacteria 

 are introduced into a susceptible animal. The extracellular toxins 

 are better known, and may be obtained from filtered culture solutions 

 by precipitation with strong alcohol. In this case they are associated 

 with the proteids which may have been present in the culture. The 

 fact that a considerable interval elapses twenty-four hours to several 

 da} T s after the injection of these toxins into a rabbit or a guinea-pig 

 before death occurs, has given rise to the inference that these sub- 

 stances are of the nature of enzymes or ferments. This view is also 

 supported by the ver}" minute quantity required to produce a fatal 

 result. According to Vaillard a dose of 0.00025 gramme of the tet- 

 anus toxin is sufficient to kill a guinea-pig. 



Indol Production. Numerous species of bacteria, as a result of 

 their vital activity, give rise to the production of indol. This may 

 be detected by cultivation in " Dunham's solution " of peptone 

 (dried peptone, I part; sodium chloride, 0.5 per cent; distilled water, 

 100 parts). Upon adding a drop of yellow nitric acid to ten cubic 

 centimetres of a culture in this medium the presence of indol will be 

 revealed by the development of a rosy red color. The presence of 

 nitrous acid in the yellow nitric acid is essential for the reaction, 

 which, however, may be obtained with pure nitric or sulphuric acid 

 if a small quantity of potassium nitrate is added to the culture one 

 cubic centimetre of a 0.2-per-cent solution. 



"Koch's Tuberculin." -This is a glycerin extract of the toxic 

 substances present in cultures of the tubercle bacillus. Crude tu- 

 berculin is obtained from liquid cultures made in veal broth to which 



