THE BUBONIC PLAGUE. 65 



typhus was recognized as a distinct disease, and distinguished 

 from the other pests of the medical profession. 



During the sixteenth and seventeenth centuries the bubonic 

 plague seems to have prevailed as an endemic disease in Europe. 



There was scarcely a year during these two centuries that this 

 disease did not assume alarming proportions at some place on 

 that continent. The last visitation in England is known as the 

 Great Plague in London, which occurred in 1665. This has been 

 very graphically described by De Foe, and has been the basis of 

 the thrilling story by Ainsworth entitled Old St. Paul. During 

 the last quarter of the seventeenth century the plague seems to 

 have gradually receded toward the East. 



During the eighteenth century it repeatedly threatened to ex- 

 tend over Europe, but seldom reached farther than Turkey and 

 the immediately adjacent territory to the north. However, there 

 were as many as eighteen distinct and severe epidemics in Con- 

 stantinople during that time. 



Up to 1841 the plague occasionally became epidemic in the Bal- 

 kan Peninsula, and there was an outbreak in the province of 

 Astrakhan in the winter of 1878-'79. Since the last-mentioned 

 years it has not appeared in Europe, but has continued in certain 

 parts of Asia. In 1894, just before the beginning of the Chinese- 

 Japanese War, it appeared in a virulent form at Hong Kong. 

 The Japanese Government sent Kitasato and the French sent Yer- 

 sin to study this disease according to the latest methods of bac- 

 teriological research. Both of these men were eminently quali- 

 fied for the work of their mission, and independently each soon 

 succeeded in isolating the specific bacillus. It is found in the 

 faeces, in the contents of the swollen glands, and in the blood. It 

 consists of rods with rounded ends, which take stains more 

 markedly at the extremities than in the middle. Sometimes the 

 germ seems to be surrounded with a capsule. In beef tea it grows 

 in chains and forms a viscid deposit on the walls and bottom of 

 the tube. It also grows on blood-serum and agar. On potatoes it 

 does not grow at ordinary temperature and only feebly at 38 C. 

 It shows but little motility and grows most abundantly at the 

 temperature of the body. 



The bacillus is pathogenic to guinea pigs, rabbits, rats, and 

 mice, and it is stated that at times of the existence of an epidemic 

 of the plague some of these animals acquire the disease, and it 

 has been suggested that they may act as agents in its spread. 

 In the above-mentioned animals the first symptoms manifest 

 themselves usually within from one to two days after inocu- 

 lation. The animal becomes apathetic, the eyes are watery, 

 the temperature rises, and death, preceded by convulsive move- 

 ments, comes on within from two to five days. The tissue around 



VOL. LI. 6 



