Ma)i and Microbes. 85 



and clergy. Jenner lived, however, to see the influential and 

 dominating peoples in the civilized world adopt his preven- 

 tive treatment. From the chance remark of a peasant to a 

 man with an open scientific mind the world has received in- 

 estimable benefits. 



To fully appreciate the value of Jenner's contribution one 

 needs but contrast the relative indifference manifested to- 

 wards the disease to-day with the terror wrought by small- 

 pox in years gone by. The conquests of Cortez and Pizarro 

 were accomplished more through the introduction of smallpox 

 than by the sword. With the Spaniard's entry into South 

 America and Mexico the disease had its inception, and then 

 proceeded to spread like a prairie conflagration. In Mexico 

 3,500,000 were suddenly slain, and no one remained to bury 

 them. Whole tribes were exterminated in the West Indies. 

 Entire races passed away in Brazil. In Quito 100,000 Indians 

 perished. Certain aboriginal cities w^re left without a single 

 inhabitant. More terrible still were the ravages of smallpox 

 among the red Indians. Catlin gives a very graphic account 

 of the extermination by smallpox of the Mandan tribe, and 

 how its great chief, Mah-to-toh-pah, the only survivor, sadly 

 reviewed the dead bodies of his own. families and warriors 

 before throwing himself down among them, and as a result 

 of total abstinence from food soon joined them on the happy 

 hunting grounds. 



IX. BACTERIA. 



It was in 1863, two centuries or more after Leeuwenhoek 

 saw the microbe, that the first bacterium of disease was caught 

 and convicted by Davaine and Rayer, although it was pre- 

 viously suspected that this particular microbe — anthr*ax — 

 was responsible for the holocaust among both cattle and men. 

 For example, in a single district in Russia, during the period 

 of three years, 56,000 horses, cattle and sheep and 528 men 

 died from anthrax infection, or "wool-sorters' disease," as 

 the human infection was termed. 



The next two decades saw the discovery of many of the 

 bacteria that are the enemies of man. Microorganisms that 

 enter man, and as a consequence cause diseases, are known as 

 pathogenic. They may belong, so far as can be determined, 

 to either the animal or the vegetable kingdom. -The former 

 are referred to as pathogenic protozoa, while the latter are 



