228 STRONG AND TEAGUE. 



trachea, but the mucous membrane here was also not reddened. 

 The cervical glands appeared normal. There was no oedema of 

 the cervical tissues. The spleen was swollen, but contained no 

 miliary abscesses. The liver showed cloudy swelling, and also 

 contained no miliary abscesses. Microscopical preparations from 

 the spleen showed a few plague bacilli. Cultures from the heart 

 and lung developed numerous colonies of the plague bacillus. 



The other dog (No. 5881) died March 21, seventeen days after 

 infection. He was considerably emaciated. The necropsy 

 showed that the lymphatic glands were nowhere swollen. There 

 were no haemorrhages or osdema in the tissues about the neck. 

 The trachea and larger bronchi contained frothy, reddish mucus. 

 The left lung was normal throughout. The upper lobe of the 

 right showed advanced hepatization throughout and sank when 

 placed in water. Two grayish wedge-shaped infarcts, measuring 

 from 1 to 1.5 centimeters at the base, were present in this lobe. 

 The whole lobe showed reddish-gray hepatization with beginning 

 resolution. The middle and lower lobes were somewhat con- 

 gested, but contained no pneumonic areas. Microscopical pre- 

 parations from the lung showed fair numbers of Bacillus pestis. 

 No other organism was present in the lung, as was demonstrated 

 by cultures. Microscopical preparations from the spleen showed 

 a few bipolar forms and a number of involution forms of the 

 plague bacillus. 



Therefore, our experiments upon dogs show that these animals 

 are only moderately susceptible to pneumonic plague but that, 

 when exposed to severe infection, they may contract primary 

 pneumonic plague and die of the disease. 



Shibayama ° showed that dogs were not very susceptible to 

 subcutaneous infection with the pneumonic strain, but that they 

 sometimes succumbed from the subcutaneous inoculation of large 

 doses or from intraperitoneal inoculation. 



Pigs. — It was stated that over 300 pigs had died during the 

 epidemic at Harbin, but there was no evidence presented which 

 showed that the disease from which they succumbed was bubonic 

 or pneumonic-plague infection, nor was any evidence submitted 

 which showed that the disease was not hog cholera or swine 

 plague. 



° Ibid., p. 46. 



