v PLAGUE IN THE RAT 117 



deeply congested. The juice of the swollen hsemorrhagic 

 inguinal gland and the juice of the spleen were crowded 

 with typical B. pestis. Droplets of heart's blood and of 

 spleen juice gave rise to crowds of colonies of B, pestis in 

 pure culture. 



With a trace of the spleen juice of this rat another 

 rat was inoculated cutaneously by way of superficial 

 abrasions at the tail-root. The animal was dead within 

 seventy hours. Post mortem : — Right inguinal glands 

 enlarged, hemorrhagic ; spleen much enlarged, dark, 

 firm ; kidneys and liver congested ; lungs congested and 

 showing numerous punctiform haemorrhages. Droplets 

 of heart's blood and spleen juice yielded crowds of 

 colonies of B. pestis in pure culture. 



One further set of experiments with this strain of the 

 Cardiff bubo B. pestis deserve to be mentioned. 



Experiment 6. — With a trace of the growth of 

 a forty -eight hours old agar subculture (directly 

 descended from the original culture), one rat (a) and 

 two mice (b) and (c) were inoculated cutaneously, each at 

 the root of the tail. 



One mouse (b) was found dead within forty-four hours, 

 the other mouse died within sixty to sixty -five hours. In 

 both animals the result of post-mortem examination was 

 the same : — Bubo in left groin crowded with B. pestis, the 

 tissue surrounding it very cedematous ; spleen much 

 enlarged, dark, firm, and crowded with B. pestis ; lungs 

 much congested ; liver pale ; kidneys large, dark red. 

 Heart's blood yielded copious growth of B. pestis. 



The rat was found dead within seventy hours. Post- 

 mortem appearances : — Big inguinal glands with haemor- 

 rhage showing crowds of B. pestis ; spleen enlarged, dark, 



