130 ORIENTAL PLAGUE chap. 



1. The Inguinal Lymph Glands. — As already mentioned, cutaneous 

 inoculation of rats in these experiments was in all cases made by- 

 rubbing a trace of the plague material on to the abraded surface (on 

 which several superficial crossed incisions had been made) of the skin 

 at the root of the tail, the hairs of this place having been previously 

 removed with scissors. Whenever this inoculation was performed 

 in the middle line the inguinal glands became subsequently involved 

 in both groins, but when the inoculation was not in the middle line 

 only the inguinal glands corresponding to the inoculated side were 

 found affected. The change in the glands consisted of enlargement, 

 one or another gland showing at the same time great congestion and 

 even haemorrhage to a greater or smaller extent. The loose con- 

 nective tissue around the gland was always congested, and some- 

 times, though not always, cedematous. Sections through the glands 

 and through the surrounding tissue showed invariably extensive 

 necrosis of the lymphatic or adenoid tissue, with a large amount of 

 blood diffused in it and in the medullary sinuses. The large blood- 

 vessels of the medulla were greatly distended with blood. Both 

 in the cortex and in the medulla the lymph sinuses in places — 

 particularly in the cortical portion — were filled with continuous 

 masses of B. pestis forming definite plugs. It was easily recognised 

 that the individual bacilli were imbedded in a hyaline ground sub- 

 stance, thus forming true zoologea ; the lymphatics both going to 

 and coming from the gland — i.e. the afferent and efferent vessels — 

 were distended by and filled with leucocytes and numerous masses of 

 B. pestis, or they were almost entirely injected with masses of the 

 latter. Similarly, the lymph spaces of the surrounding fat tissue 

 were in some instances literally filled with the bacilli. That the lymph 

 vessels passing to the glands should be found containing abundance 

 of B. pestis was to be expected, since the latter would readily be 

 carried from the inoculated spot of the skin of the tail to the lymph 

 glands. Also it was to be anticipated that B. pestis would readily 

 multiply in these lymph vessels, in the lymph spaces of the groin, 

 and in those of the gland itself, and thus produce continuous masses 

 filling these lymphatics. But what was not looked for, and which is 

 a point of great interest, is the fact that all the venous blood-vessels, 

 including many capillaries of the tissue surrounding the gland, like- 

 wise contained large and small continuous streaks and masses of 

 B. pestis. Such a condition is not or is only very rarely present in 

 other organs. It is not observed either in the kidney or intestine or 



