442 THE BACILLUS OF TYPHOID FEVER. 
staining the spores of other bacilli, and, in short, present none of the 
characters which distinguish spores, except the form and high re- 
fractive power. 
The typhoid bacillus retains its vitality for many months in cul- 
tures; the writer has preserved bouillon cultures for more than a year 
in hermetically sealed tubes, and has found that development 
promptly occurred in nutrient gelatin inoculated from these. Dried 
upon a cover glass, it may grow in a suitable medium after having 
been preserved for eight to ten weeks (Pfuhl). When added to 
sterilized distilled water it may retain its vitality for more than four 
weeks (Bolton), (forty days Cassedebat), and in sterilized sea-water 
for ten days (De Giaxa). Added to putrefying faeces it may preserve 
its vitality for several months (Ufflemann), in typhoid stools for three 
months (Karlinski), and in earth upon which bouillon cultures had 
been poured for five and one-half months (Grancher and Deschamps). 
In hanging-drop cultures this bacillus may be seen to exhibit very 
active movements, the shorter rods rapidly crossing the field with a 
darting or to-and-fro, progressive motion, while longer filaments 
move in a serpentine manner. 
In addition to the volatile fat acids which, according to Brieger, 
are formed in small amounts in cultures of the typhoid bacillus, and 
to lactic acid formed in solutions containing grape sugar, a basic 
substance possessing toxic properties has been isolated by the chemist 
named—his typhotoxine (C,H,,NO,). Brieger supposes that other 
basic substances are likewise formed, but believes this to be the speci- 
fic product to which the pathogenic action of the bacillus is due. It 
is a strongly alkaline base, which produces in mice and guinea-pigs 
salivation, paralysis, dilated pupils, diarrhoea, and death. 
Numerous experiments have been made to determine the amounts 
of various germicidal agents required to destroy the vitality of this 
bacillus, and the action of antiseptics in restraining its development. 
For the results of these experiments the reader is referred to the 
sections in Part Second relating to the action of antiseptics and disin- 
fectants. 
Pathogenests.—The very numerous experiments which have been 
made on the lower animals have not been successful in producing in 
any one of them a typical typhoid process. Nor is this surprising, 
in view of the fact that, so far asis known, no one of them is liable to 
contract the disease, as man does, by the use of infected food or 
water. 
The experiments of Frankel and Simmonds show that when con- 
siderable quantities of a pure culture of this bacillus are injected into 
the circulation of rabbits through the ear vein, or into the peritoneal 
cavity of mice, a certain proportion of the inoculated animals die, 
