1424 



PLAGUE 



England, but only a few cases of bubonic plague in man. The 

 tarbagan suffers at times from plague, but the epizootic is not 

 extensive, and its direct relationship to human plague is negligible. 

 Spermophilus citellus, the marmot, is susceptible to plague. 



Attention may be called to epidemic diseases in the lower animals due to 

 bipolar staining bacilli, somewhat resembling the plague germ. We have 

 observed one such epidemic in cats in Ceylon in 1904. A bipolar staining 

 bacillus was found to be the cause {Bacillus felisepticus Castellani), but the 

 cultural characters were somewhat different from those of the true plague 

 bacillus. 



Pathology. — Plague is a hsemorrhagic septicaemia in the rat, which 

 is communicated to the human being by flea-bites. The site of 

 inoculation is sometimes marked by a vesicle, the contents of which 

 contain the Bacillus pestis in considerable numbers. The bacilli 

 then travel via the lymphatics to the nearest lymphatic glands, 

 which they may traverse, and, passing through the thoracic duct, 

 enter the blood stream, and cause a septicaemia. More usually they 

 remain and grow in the peripheral lymph sinuses of those glands in 

 which they or their toxins cause degenerations of the cells, peri- 

 glandular serous infiltration, and, later, degeneration of the Vv^alls 

 of the bloodvessels and haemorrhage. The lymphatic glands are 

 matted together by the exudation from the primary bubo. The 

 glands usually affected are the femoral, inguinal, axillary, ihac, or 

 cervical, which may briefly be classified into the groin, the axillary, 

 and cervical glands. 



The Indian Conmiission points out that the reason why the 

 groin glands are so frequently attacked is simply because they 

 drain the largest skin area, for they say that the areas drained by 

 the glands of the neck, axilla, and groin are in the proportions of 

 1 : 1-8:5, while the number of cervical, axillary, and inguinaJ buboes 

 are in the proportions of i : 1-3: 5-8, and that therefore there is no 

 seat of election as to where the plague bacillus enters. 



From the primary bubo the bacihi may travel along the lymphatics 

 to the next chain of glands, in which they produce the secondary 

 bubo, and from this they may enter the blood stream via the 

 lymphatics. The bacilli, however, may gain direct access to the 

 blood stream through the injuries to the walls of the veins in the 

 primary bubo. Once the blood stream is reached the disease 

 becomes a septicaemia, and affects the lymphatic glands, forming 

 tertiary buboes; the lungs, causing bronchitis and secondary 

 pneumonia; the spleen, liver, kidneys, skin, and other organs; and, 

 finally, leaves the body through the kidneys, skin, and mucosae, 

 escaping in the urine, faeces, and sputum (if there is pneumonia), as 

 well as by any discharges or hcEmorrhages from the skin. The 

 excretion, via the sputum and saliva, can proceed for a period of at 

 least forty-eight days after the temperature is normal. Further, 

 as in chronic plague in rats, the bacilli may be found in abscesses 

 some two and a half months after an attack. The chemical patho- 

 logy of the disease is not well known. 



