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 water. 
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 pneumoniz 
croupose (‘diplococcus pneumonie’); 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 
days—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 very 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 Productton.—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, 1 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- 
