LEPROSY. 615 



spleen contain many nodules which may be as large as 

 a hazelnut, and which are frequently caseated in the cen- 

 ter. The organism is called Bacillus pseudotuberculosis 

 rodentium or Streptobacillus pseudotuberculosis dor. 



The disease in mice is caused by a diphtheria-like or- sheep. 

 ganism called Bacillus pseudotuberculosis murium and 

 is pathogenic especially for the gray mouse. 



A similar infection in sheep is of more importance and 

 occurs with some frequency. It is called pseudotubercu- 

 losis ovis, and the bacillus has a corresponding name. 

 The organism is supposed to gain entrance through 

 wounds in the feet and legs, following which the adja- 

 cent lymph glands become involved, and the infection 

 may be transferred to the lungs and other organs 

 through the lymphatic circulation. The lesions are 

 nodular, of varying size, usually surrounded by a fibrous 

 capsule, and are either semipurulent or undergo early 

 caseation. They may be found in all the visceral or- 

 gans. 



An organism resembling that cultivated from the 

 sheep has occasionally been found in nodular conditions 

 in cattle. 



II. LEPROSY. 



Leprosy existed iii Egypt in prehistoric times course of 

 and extended to other lands only when inter- 

 course was established. It reached Greece at 

 about 345 B. C., Italy in the first century 

 before Christ, and from the latter country 

 extended to Germany,, France and Spain. Cru- 

 saders returning from the Orient also brought back 

 the disease in later times and eventually all 

 Europe was infected. Leprosy is known to have 

 existed in Great Britain in the tenth century, and 

 from that country it was carried to Iceland and 

 Greenland. From Germany it extended to the 

 Scandinavian countries, and from the latter to 

 Finland and Russia. It also reached Russia from 

 the South and East, and in the South it was at 

 one time called the Crimean disease. The West 

 Indies and South America probably were infected 



