ECOLOGICAL BACKGROUND AND GROWTH BEFORE 1900 



29 



experiments on the subject. King (1883) 

 gave nineteen reasons why mosquitoes 

 should be considered as possible vectors of 

 malaria. King knew about Finlay's work, 

 but he deserves credit for extending it to 

 malaria at a time when even certain ento- 

 mologists well acquainted with mosquitoes 

 rejected the idea. 



The relations that had been established 

 by 1900 are summarized in Table 1. We 

 have taken the liberty of bringing informa- 

 tion concerning the causative organisms 

 and insect vectors up to date rather than 

 give here the more imperfect statements of 

 1900. 



Medical entomology was in a state of 

 rapid growth at the end of the period cov- 

 ered by the present chapter, and scholarly 

 consolidation of the field had already be- 

 gun; this was shown by the appearance of 

 the first comprehensive, critical and histori- 

 cal study of the known disease-carrying 

 activities of arthropods, that by Nuttall 

 (1899). The medical masterpiece by Smith 

 and Kilbourne (1893) deserves independent 

 mention, not only because of its medical 

 significance, but also because of its careful 

 and critical use of the techniques of field 

 experimentation. 



Forbes, an alert student of the literature 

 of the subjects with which he dealt as 

 well as with natural phenomena themselves, 

 may well have had many of these develop- 

 ments in applied entomology in mind when 

 he wrote the following orienting paragraph 

 (1895) as an introduction to his discussion 

 of the diseases of the chinch bug: 



"... Another division of biological science, 

 little known to the general public by its name 

 as yet, and but lately (distinguished as a 

 separate subject, ... is now commonly called 

 oecology. It is the science of the relations of 

 living animals and plants to each other as liv- 

 ing things and to their surroundings generally. 

 It deals with tlie ways in wliich heat and light, 

 moisture and drouth, soil and climate, and 

 food and competitors and parasites and pre- 

 dacious enemies, and a long list of agencies 

 additional, act upon living things, and the 

 ways in which these living things react in turn; 

 it includes, in short, the whole system of life 

 as exhibited in the interactions between the 

 plant or animal and the environment, living 

 and without life. It is a very comprehensive, 

 complicated, and important subject; how com- 

 prehensive and important we see at once when 

 we learn that the whole Darwinian doctrine 

 belongs to it on the one hand, and that all 

 agriculture depends upon it on the other. It 



covers, indeed, the whole field of active life 

 and all forms of matter and energy as affecting 

 living things in any way." 



EVOLUTION: 

 STRUGGLE AND COOPERATION 



The history of the growth of knowledge 

 of organic evolution has been told fre- 

 quently and well. We need only call 

 attention to the twin facts (a) that the his- 

 tory of the rise of evolution in its modern 

 biological connotation repeats much of the 

 history of ecology in that many of the same 

 men were involved, and {b) that the sub- 

 ject matter of each of these two aspects of 

 biology strongly overlaps. 



The nearer we approach modern times 

 and modern preoccupations, the greater is 

 the divergence in men as well as in matter. 

 Although shadowy ideas of evolution, and 

 even forerunners of the theory of natural 

 selection, are much older (cf. Zirkle, 1941), 

 for the purposes of this sketch we may well 

 begin with Buffon, the great theoretical 

 biologist of the eighteenth century. We get 

 a glimpse of the essence of his evolutionary 

 ideas from the following quotation from 

 his Histoire Naturelle (Paris, 1749 ff.: 

 translation quoted from Dendy, 1914) : 



"If we again consider each species in differ- 

 ent climates we shall find obvious varieties both 

 as regards size and form; all are influenced 

 more or less strongly by the climate. These 

 changes only take place slowly and impercep- 

 tibly; the great workman of Nature is Time: 

 he walks always with even strides, uniform 

 and regular, he does nothing by leaps; but 

 by degrees, by gradations, by succession, he 

 does everything; and these changes, at first 

 imperceptible, little by little become evident, 

 and express themselves at length in results 

 about which we cannot be mistaken." 



Buffon's main contribution to evolution- 

 ary biology was the idea that the environ- 

 ment can permanently affect the life of 

 organisms by the process now called en- 

 vironmental induction. Buffon influenced 

 Erasmus Darwin's ideas, and also those of 

 Lamarck. Although he anticipated Malthus 

 in understanding the implications of popu- 

 lation pressure, and while he had a clear 

 appreciation of the struggle for existence, 

 Buffon was not a consistent thinker, and he 

 may be as truly classified with Cuvier as 

 a catastrophist as with Lamarck and Eras- 

 mus Darwin as a forerunner of modern 

 evolutionary views. 



