230 CHANNELS OF INFECTION, 
Infection through the mucous membrane of the intestine no 
doubt occurs in certain diseases. This is believed to be a common 
mode of the infection of sheep and cattle with anthrax, and probably 
also in the infectious disease of swine known as hog cholera. The 
anthrax bacillus would be destroyed by the acid secretions of the 
stomach, but if spores are present in food ingested they will reach 
the intestine. The experiments of Korkunoff do not, however, sup- 
port the view that infection is likely to occur in this way. In a series 
of experiments upon white mice fed with bread containing a quantity 
of anthrax spores the result was uniformly negative, but exception- 
ally infection occurred in rabbits. The same author obtained posi- 
tive results in rabbits fed with food to which a pure culture of the 
bacillus of chicken cholera had been added. 
Buchner, in experiments upon mice and guinea-pigs fed with 
material containing anthrax spores, obtained a positive result in four 
out of thirty-three animals. This is no doubt the usual mode of in- 
fection in typhoid fever in man. 
Infection may also occur through the mucous membrane of the 
respiratory organs. This has been demonstrated by several bac- 
teriologists, and especially by the experiments of Buchner, who 
mixed dried anthrax spores with lycopodium powder or pulverized 
charcoal, and caused mice and guinea-pigs to respire an atmosphere 
containing this powder in suspension. In a series of sixty-six experi- 
ments fifty animals died of anthrax, nine of pneumonia, and seven 
survived. That infection did not occur through the mucous mem- 
brane of the alimentary canal was proved by comparative experi- 
ments in which animals were fed with double the quantity of spores 
used in the inhalation experiments. Out of thirty-three animals fed 
in this way but four contracted anthrax. That infection occurred 
through the lungs was also demonstrated by the microscopical ex- 
amination of sections and by culture experiments, which showed that 
the lungs were extensively invaded, while in many cases the spleen 
contained no bacilli. Positive results were also obtained with cul- 
tures of the anthrax bacillus not containing spores, which the ani- 
mals were made to inhale in the form of spray. But in this case a 
considerable quantity was required, and a sero-fibrinous pneumonia 
was usually produced as well as general infection; the inhalation of 
small quantities gave no result. Positive results in rabbits were also 
obtained by causing them to inhale considerable quantities of a spray 
containing the bacillus of chicken cholera, 
The fact that large quantities of a liquid culture of these virulent 
bacilli were required to infect very susceptible animals by way of 
the pulmonary mucous membrane, and that Buchner failed to cause 
the infection of these animals with small quantities of a pure culture 
