APPLIED SYSTEMATICS — SCHMITT 333 



tant thing. It made species sanitation possible, and definitely effective, 

 in a comparatively short space of time, and today enables the Brazilian 

 Government to keep this dangerous enemy out of the country. 



THE BLACK DEATH 



The story of the plague— bubonic plague, the highly fatal Black 

 Death of the Middle Ages — and of its spread and control in India, 

 Ceylon, and elsewhere parallels that of malaria, and, like it, turns 

 upon the critical recognition of species of insects — in this case, fleas. 



Much of our knowledge of the dissemination of plague by fleas 

 we owe to two men, L. Fabian Hirst, health officer at Colombo, Ceylon, 

 and Nathan Charles Rothschild, an authority on the kinds of fleas, 

 who discovered that the prevalent rat fleas of India and the Orient 

 did not constitute a single species, as previously believed, but were 

 three very closely allied species. It was Hirst who first suggested 

 and then demonstrated that these fleas had quite different biting 

 habits and different appetites for human blood, and thus varied in 

 their effectiveness in transmitting plague from rat to rat, and rat to 

 man. Their discoveries established the geographic distribution of 

 the different species of rat fleas as one of the most important factors 

 governing the spread of plague, and for the first time furnished a 

 logical explanation for the relative immunity of certain parts of 

 India and Ceylon to both epidemic and epizootic bubonic plague. 



This discovery was the natural outcome of the purely zoological 

 researches of Rothschild and others on the systematics of fleas. 



IN TIME OF WAR AND IN NATIONAL DEFENSE 



Though not accorded recognition in the headlines of the daily press 

 or rewarded with oak-leaf clusters, the taxonomists made many note- 

 worthy but unheralded contributions to the waging and winning of 

 the late great war with their prompt identification of the many things 

 about which vitally important information was urgently needed. 



In war we have much the same problems in medicine, epidemics, 

 disease, and health as in times of peace, only more intensified and more 

 urgently calling for solution or alleviation. The immobilization of 

 armies by attacks of malaria in the European theater and the casual- 

 ties, if we may call them that, from the same cause and insect-borne 

 diseases in the Pacific became so serious that it was of utmost im- 

 portance that the mosquitoes, fleas, ticks, and other pests or vermin 

 be identified without delay. Those that could not be named by the 

 sanitary and medical units in the field were given the very highest 

 priority to Washington for immediate determination. 



