408 BACTERIOLOGY. 
typical pathological changes have regularly followed — 
animal inoculations, but in most cases they could easily 
be traced to the toxemia produced by the substances in 
the bodies of the bacilli injected, not necessarily accom- 
panied by the growth of the organism, rather than to 
infection due to the development of the typhoid bacillus 
in the tissues. 
- Inacertain number of cases subcutaneous and intra- 
peritoneal inoculations in animals have been productive 
of more or less typical typhoid lesions. Among the 
most successful efforts in this direction are the experi- 
ments of Cygnaeus and Seitz, who, by the inoculation 
of the typhoid bacillus into dogs, rabbits, and mice, 
produced in the small intestines conditions that were 
histologically and to the naked eye analogous to those 
found in the human subject, but their resulis were not 
constant. Of a number of experiments made by Ab- 
bott, with the same object in view, only one positive 
result followed the introduction of typhoid bacilli into 
the circulation of rabbits. In this case the ulcer in 
the ileum was macroscopically and microscopically iden- 
tical with those found at autopsy in the small intestines 
of the human subject dead of this disease. The bacilli 
were found in the spleen. 
Experiments indicate that the presence of other bac- 
teria in the body, and of exposure to the effect of nox- 
ious gases in lowering the natural resistance of the 
individual, render him more susceptible to infection 
from typhoid fever and, indeed, from other infectious 
diseases. 
But whatever conclusions may be drawn from these 
results, with regard to the typhoid process in animals, 
typhoid fever in the human subject is now recognized 
