GEOGRAPHIC DISTRIB UTION OF B UBONIC FLA G UE 105 



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mild cases may occur, not onl}' because of the slight susceptibilit}' of 

 the individual, but also because of the " attenuated " virulence of 

 the specific germ. In the eighteenth century, the beginning of sani- 

 tary science, isolation of the sick and seaboard quarantines came to 

 the aid of these natural agencies, and did much in the way of arrest- 

 ing the progress of this pestilential disease. At the present day these 

 measures, together with disinfection by heat or chemical agents, are 

 relied upon by sanitarians with great confidence as being entirely 

 adequate for the exclusion of this disease or for stamping it out if it 

 should efiect a lodgment in localities where an enlightened public 

 sentiment permits the thorough execution of these preventive meas- 

 ures ; but when the disease prevails among an ignorant population 

 which strenuously objects to the carrying out of these measures, the 

 contest between the sanitary oflficer and the deadly germ is an un- 

 equal one, and the stamping out of an epidemic becomes a task of 

 great magnitude, if not entirely hopeless. This is illustrated by the 

 experience of the English in their encounter with bubonic plague in 

 their Indian Empire. 



I shall not attempt to trace the history of plague in Asia, and, in- 

 deed, reliable data for such an attempt are wanting, but we know 

 that bubonic plague has frequently prevailed in various parts of Asia 

 Minor, in India, and in China. According to Hirsch,the first trust- 

 worthy information of the occurrence of plague in India dates from the 

 year 1815, when it appeared in the low country of Hindostan, where 

 it has prevailed to a greater or less extent up to the jn-esent da3^ 



Tropical Africa has never suffered from the plague, and in general 

 it may be stated that a tropical climate is less favorable to its epi- 

 demic extension than a semi-tropical or temperate one. This is 

 shown by the records relating to mortality from the disease in Alex- 

 andria, Egypt. During the epidemic period extending from 1834 to 

 1843, the mortality invariably fell off' during the months of June, 

 July, and August, and a recrudescence of the disease occurred in De- 

 cember and January, the acme of mortality being reached in March. 



All authorities agree that filtli, famine, and overcrowding of dwell- 

 ings are potent factors in the ])roi)agation of the plague, and it is for 

 this reason that it is to a large extent a disease of the poor, and that 

 epidemics are especially liable to occur during times of distress from 

 insufficient harvests or the ravages of war. The idea that the i)lague 

 may originate de novo as a result of tlie causes mentioned as favor- 

 able to its ])ropagation is not sup[)orted l)y satisfactory historical 



