62 



THE HISTORY OF ECOLOGY 



4. The studies are theoretically impor- 

 tant, especially in relation to the natural 

 population, the community, statistics ot 

 host-parasite interactions (epidemiology), 

 social origins and social faciUtation, and 

 evolution and speciation. 



A final development needs mention: 

 Cleveland's work (1924) on the symbiotic 

 relationship between wood-feeding termites 

 and their intestinal flagellates. Here it was 

 demonstrated that the latter, by secreting 

 a cellulose-digesting enzyme, made wood 

 available as food for the termite colony. 

 In turn, the termite gut furnished a micro- 

 niche for the Protozoa. This study was sig- 

 nificant in that it placed symbiosis on an 

 analytical basis and furnished impetus for 

 excellent research in the next decade. 

 Cleveland himself, in collaboration with 

 Hall, Sanders, and Colher, brought forth 

 in 1934 a comprehensive monograph on 

 the symbiosis between the roach Crijpto- 

 cercus and its intestinal Protozoa. 



This concludes our survey of tlie active 

 third decade. We have examined the trends 

 and developments in ecology that centered 

 both around the physical and the biotic en- 

 vironment. We have seen that this was an 

 era when ideas were just starting to emerge 

 into a broader ecological framework and 

 when ecological research ceased being 

 helter-skelter and started to acquire focus. 



1931-1942 



In discussing this period we shall ex- 

 tend the interval beyond a decade (to 

 1942) in order to include several significant 

 trends that appeared in the last several 

 years. In this section it is our plan to make 

 these points: 



1. Ecology was exceedingly active, both 

 in terms of volume of work and in qual- 

 ity of ecological effort. 



2. Ecology gave signs of maturation. It 

 began to develop, crystalUze, and coordi- 

 nate principles of its own. 



3. There was a newborn interest in an 

 ecological framework of theory— a theorv 

 based, not on speculation, but largely on 

 empirical evidence. 



4. By 1942 ecology, with notable excep- 

 tions, was in a healthy and lusty state and 

 was looking forward to the decades to 

 come. 



It is not feasible to survey the progress 

 of this decade by the methods used in the 



preceding pages of citing research papers 

 and suggesting their influence on the 

 growth of the subject. As a more mature 

 science, ecology in the thirties gave birth 

 to many sorts of activities, which index and 

 epitomize its growth. We shall try to in- 

 dicate what these activities were and then 

 discuss them in enough detail to deHneate 

 the contribution that was theirs.** This 

 should serve also as a sort of summary for 

 the entire historical treatment in the sense 

 that it will show the state of the science 

 in its most modern dress. To our minds, 

 these activities fall into the following larger 

 categories: first, books; second, journals 

 available to and used by ecologists both for 

 recording research and surveying segments 

 of the field; third, review articles in review 

 journals; fourth, symposia; and last, articles 

 of particular significance in the synthesis of 

 ecological theory. 



Books 



In discussing the books of the decade 

 we stress the point, as we have done for 

 all the historical treatment, that the Ust is 

 a sample and not a complete tabulation. 

 It is, however, comprehensive enough to 

 cover the field thoroughly. The books pub- 

 Ushed between 1931 and 1942 fall into 

 these eight categories: 



(a) General texts or reference works pri- 

 marily ecological in character; 



(b) Books emphasizing the population 

 primarily; 



(c) Books dealing with sociality and social 

 organization; 



(d) Books stressing the ecological aspects of 

 zoogeography and dispersal; 



(e) Books dealing with evolutionary and 

 speciation aspects and containing an 

 ecological (as well as genetic) treat- 

 ment; 



(/) Books on ecological aspects of behavior; 



(g) Books on applied ecology; 



(h) Books on theoretical and philosophical 



aspects that are difficult to place in the 



foregoing categories. 



A fist of books according to this classifi- 

 cation and in the order of their pubhcation 

 dates is given at the end of this chapter. 



At this place a word of emphasis is in 

 order about the Clements and Shelford Bio- 

 Ecology (1939) and the movement it rep- 



** It is obvious, of course, that the account of 

 all these "activities" is reflected in final analysis 

 in the publication of research data. 



