vii INFECTION OF ANIMALS WITH PLAGUE 163 



in the submucous tissue, is a large blood-vessel distended 

 by blood, and surrounding it is a lymph space densely filled 

 with a continuous mass of B. pestis. Similarly at 4, 

 lymph vessels situated between the inner circular and 

 outer longitudinal layer of the muscular coat are filled 

 with continuous masses of B. pestis. In the figure 

 these lymph spaces at 3 and 4 appear dark ; but in the 

 actual specimen stained with methyl-blue and eosin these 

 parts are deeply blue, while the blood of the blood-vessels 

 is pink. Under a sufficiently high magnification the fact 

 that the masses are composed of B. pestis is easily 

 recognised. 



In this animal, as also in others yet to be described — 

 rats, guinea-pigs, and mice — sections through the hemor- 

 rhagic patches of the mucous membrane over and around 

 the affected Peyer's glands show some villi which present 

 a remarkable appearance. Continuous streaks and masses 

 of B. pestis (Figs. 80, 81, 87, and 89) not only cover the 

 surface of the villi denuded of their epithelium, but 

 extend between the tissue elements in the same reticular 

 fashion as chyle does during absorption ; moreover, in 

 some instances the central chyle vessel appears distended 

 and filled with the B. pestis. In particular villi the 

 tissue is completely deranged by effused blood in which 

 appear numerous B. pestis. Continuous masses of 

 B. pestis are found also around the fundus of the Lieber- 

 kiihn crypts, surrounding these like lymph spaces, as also 

 within the cavities of the crypts. 



In Fig. 76 the blood-vessels mentioned at 3 (Fig. 75) 

 are shown somewhat more magnified ( x 300). They are 

 filled with blood in which abundance of small and large 

 masses of B. pestis can be seen (dark in the figure) ; the 



