82 WOODWARD 



monest disorders, in certain localities, with which man in his 

 struggle for existence has had to cope ; and before the dis- 

 covery of the properties of Peruvian bark it must have been a 

 very serious affliction by reason of its secondary if not by reason 

 of its primary effects. The symptoms, course, and distinguish- 

 ing characteristics of the disease, as well as the remedies there- 

 for, were long known, however, before it was suspected that the 

 mosquito had anything to do with its dissemination. Bad 

 water, foul air, and sudden or extreme changes of temperature 

 were supposed to be promoting causes. The dampness of 

 marshes, swamps, and other areas holding stagnant water was 

 held to be an especially common attendant, if not inducing, con- 

 dition. There was, indeed, no lack of acute and painstaking 

 observations and no lack of ingenious and well-supported 

 hypotheses with regard to this widely prevalent but obscure 

 disorder. The details of its diagnosis, prognosis, nature, and 

 causation as laid down in the medical manuals of a few decades 

 ago, are particularly interesting and instructive reading now in 

 view of recent developments. For example, Hartshorne in his 

 " Essentials of the Principles and Practice of Medicine," pub- 

 lished in 1 87 1, gives the following explanations : 



*' No disease has ordinarily so regular a succession of definite 

 stages as intermittent fever, namely the cold, the hot, and the 

 sweating stage." * * * << Upon the origin of malarial fevers," he 

 adds, *' the following facts seem to be established : i. They are 

 reasonably designated as autumnal fevers, because very much the 

 largest number of cases occur in the fall of the year. Spring 

 has the next greatest number of cases. 2. They are always 

 strictly localized in prevalence. 3. They never prevail in the 

 thickly built portions of cities. 4. An average summer heat 

 of at least 60° F. for two months is necessary for their develop- 

 ment. Their violence and mortality are greatest, however, in 

 tropical and subtropical climates. 5. They prevail least where 

 the surface of the earth is rocky ; and most near marshes, shal- 

 low lakes and slow streams. The vicinity of the sea is free from 

 them, unless marshes lie near it. 6. The draining of dams or 

 ponds, and the first culture of new soil, often originates them. 



