30 
required to restrain the growth and multiplication of the other eight- 
een different pathogenic and saprophytic bacteria tested. 
GLYCERIN AS A GERMICIDE. 
Glycerin has a distinct, though exceedingly feeble, germicidal action. 
It probably acts by virtue of its great affinity for water, abstracting 
this substance from the germ. 
As a rule, glycerin destroys the micrococci of suppuration, whether 
these be in pure culture or in the pus itself, within two weeks. This 
action, like that of all germicides, depends for its activity upon the 
temperature. Pus cocci may live in glycerin for months in the ice 
chest. The}^ would die in a week at the bod}- temperature. 
Gl}xerin seems to be a selective poison for the bacillus of diphthe- 
ria, which in all of our experiments died much more quickly than any 
of the other organisms tested. 
The bacteria of the typhoid and colon group often show a marked 
resistance to the effects of glycerin in strong proportions. 
Glycerin asserts its greatest germicidal effect during the first twenty- 
four hours. The remaining members of the colonies which resist its 
action for this first period succumb very slowly. 
Gl}merin in all proportions has practically no eff ect upon endogenous 
spores. We have kept anthrax spores alive and virulent two hundred 
days in the stronger percentages and at warm temperatures. 
TETANUS IN GLYCERIN. 
Tetanus spores in pure culture, freed of all organic matter and washed 
free of toxin, ma3Gose their virulence in ghxerin in thirty days at the 
body temperature, but the}^ live for months (one hundred and eighty 
days) at room temperature or in the ice chest. Glycerin, therefore, 
can not be depended upon to purif}^ vaccine or other organic matter 
containing this contamination. The virulence of the spores is lost 
long before they actually die, for they still retain the power of grow- 
ing and multipl^Tng if placed under favorable conditions. Under these 
circumstances they also regain their original pathogenic properties. 
Glycerin has practically no effect upon tetanus toxin. We found 
such toxin added to glycerin to be active for sixty days at the body 
temperature and one hundred and eighty days at room temperature 
or in the ice chest. 
O 
