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The swellings may appear early. In fact, they may be existent before many definite symptoms of the disease are present. In other cases, they appear late, during the course of a well defined case of septicæmic plague. The reasons for this variability in the time of their appearance, is by no means obvious. Again such a swelling may be single, double, or multiple, without a satisfactory explanation of the process at work being evident. It has been my experience to find general lymphatic enlargement in ordinary bubonic plague. The glands are moderately increased in size, cedematous and show extravasations of blood especially in the cortical layers.
Not only is this general glandular enlargement found in bubonic plague, but it is met with in cases of other types of the disease. In the purely septica nic type, this enlargement is one of the commonest changes found post-mortem. In the pneumonic form, ie., secondary lung plague, the glands are also similary affected. In primary pneumonic plague, hyperæmia and petechial hæmorrhages occur in the lymphatic glands without much evidence of enlargement. This evidence points to the ready action of the plague virus on the general lymphatic system. The evidence gathered from my experience would appear to show that the disease, no matter what type it ultimately assumes, is of a septicaemic nature.
In plague, the lymphatic apparatus is one of the first systems to be affectel. The plague virus would appear to possess a marked affinity for lymphatic tissue. The preference for certain body tissues is known in bacteriology.
The pathological changes produced by the plague virus in lymphatic tissue is, in my opinion, merely one of degree.
In septicemic cases with no bubonic formations we find evidence of glandular enlargement. No particular gland or series of glands is affected. All are generally hyperæmic and où careful examination show minute petechial hæmorrhages. Occasionally during the course of such a septicæmia, a bubo may develop out of some of these slightly affected series of glands.
In pneumonic cases, the condition is similar to that found in septicemic plague. Buboes may complicate pneumonic plague and vice versa.
In the majority of cases of plague, some definite enlargement takes place. This takes place early, in fact, sometimes so early as to be regarded as practically the initial manifestation of the disorder.
Bubonic plague, in the absence of primary pneumonic plague, forms the majority of the cases net with during most epidemics. Therefore we have in plague a disease of a septicæmic nature. The B. pestis multiplies in the general blood stream and primarily exerts its deleterious action on the lymphatic apparatus. In this, swelling, ædema, and hæmorrhagic extravasation take place. These changes are accompanied by a periglandular haemorrhage, which is diffuse. Evidences are now available as to the action of the virus on the peripheral circulatory apparatus.
Further changes are produced generally in the body, particularly those of degeneration.
Summing up, from a pathological standpoint the various lesions met with during the course of a typical case, one is rather drawn away from the idea that buboes are the result of infection through the skin and mucous membranes in the immediate neighbourhood. It would appear, on the other hand, that the formation of buboes in the body is dependent on the micro-organism itself, its virulence, and the individual disposition of the person or persons attacked. Simple hæmorrhagic extravasations are quite as common as buboes. They also occur in fairly definite localities in the body, yet no one has thought them worthy of consideration from the point of view of the focus of entry of the B. pestis into the body.
in man.
Many of the septicemic diseases met with in animals are analogous to plague- From a clinical point of view, the appearances presented by such animals, have so resembled plague, that Orientals are firmly convinced that epidemics of a similar disease to plague break out amongst their animals some time- previous to the occurrence of plague in man. The condition of septicemia hæmorrhagica found in cattle in Hongkong resembles plague pathologically. In both diseases do we find general hyperemia, general lymphatic enlargement, the