156 ORIENTAL PLAGUE chap. 



more so) to the entrance of the B. pestis as is the corium 

 of the skin. In the mucous membrane there is no pro- 

 tective dry cuticle to be overcome as in the skin ; 

 seemingly, therefore, B. pestis has only to be lodged in 

 the soft surface epithelium — which, under the many 

 mechanical operations involved in the process of mastica- 

 tion, deglutition, and digestion, might occur — in order to 

 become actually " inoculated." The introduction with 

 positive result by the German Commission of B. pestis 

 into the conjunctival sac of rats would be an illustration 

 in point ; and here the mechanical action of the eyelids 

 would be capable of ensuring such " inoculation." 



It is matter of history, however, that numerous experi- 

 ments made in the laboratory in feeding rats and other 

 susceptible animals with plague cultures, and with fresh 

 organs of animals dead of plague, have commonly failed. 

 Leaving out those positive instances 1 in which cervical 

 buboes and plague occurred in a rodent (guinea-pig, rat, 

 mouse) after gnawing the bones as well as the viscera of a 

 plague animal — positive instances which might have been 

 really due to inoculation of an abrasion caused by sharp 

 points of bone splinters, — negative results have hitherto 



1 In the large number of experiments of feeding made by the German Plague 

 Commission, there were only very few cases indeed in which a direct infection via 

 the intestine could, from the anatomical lesions found on post-mortem, be con- 

 sidered to have actually occurred — leaving out those instances in which infection 

 clearly is referable to having taken place in the fauces ; and in the positive 

 instances (second type of the Commissioners) the intestinal infection appears to 

 have occurred in rats only after feeding them with rats dead of plague. 



The Austrian Plague Commission, in their feeding experiments, seem to have 

 had positive cases of septicemic plague in guinea-pigs and rats, but of a character 

 which clearly denoted infection to have taken place from the mouth or fauces ; but 

 they appear to have had some few positive intestinal infections (Peyer's patches 

 hsemorrhagically infiltrated or necrotic, and the same condition of the mesenteric 

 glands) in guinea-pigs only, after feeding them on animals dead of plague. But 

 most of their feeding experiments (on rats and mice) were negative qud intestinal 

 infection ; positive infection clearly occurred from the mouth or fauces. 



