ANTHRAX. 



28l 



for development into the vegetative forms ; and as they are 

 developed they make their way, especially through damaged 

 epithelial cells which they gradually push to one side, into 

 the deeper layers of the intestinal wall, into the lymph 

 channels, or directly into the blood vessels, so giving rise, in 

 many cases, to a general infection. 



Susceptibility of animals to infection through the intes- 



JK* 





Photo-micrograph of Anthrax bacilli in the blood vessels of the mesentery of a mouse. 

 At one or two points the bacilli may be seen lying in the substance of some of the 

 white blood cells (phagocytes), x 375. 



tinal canal varies very greatly, the guinea-pig, which is very 

 susceptible to the disease conveyed by inoculation, withstand- 

 ing a very large dose of the spores when given by the 

 stomach, whilst sheep and cattle, both of which are more 

 resistant as regards inoculation, are comparatively easily in- 

 fected through the alimentary canal. I have stated that at 

 the point of inoculation in animals there is usually no evi- 



