46 



THE HISTORY OF ECOLOGY 



evaluate the influence of works like this on 

 ecological development. Then there were 

 books such as Seton's Life Histories of 

 Northern Animals (1909). These contrib- 

 uted much that was useful to the ecologist. 

 Seton's book combined a wealth of infor- 

 mation about life histories and habits with 

 an extensive bibliography. Von Neumayer 

 (1906) published his two volume compen- 

 dium on exploration. Adams (1913 p. 63) 

 says of this study: "A very important work, 

 particularly for the traveling naturalist. 

 Chapters by specialists, valuable references 

 on collecting natural history specimens, and 

 other phases of scientific exploration are in- 

 cluded." More technical natural history 

 studies of this period are typified by the 

 papers of Reighard (1903), Andrews 

 (1904), and Forbes (1907). 



Reighard's paper, on the "Natural His- 

 tory of Amia calva," published as a tribute 

 to the Harvard zoologist Edward Laurens 

 Mark, is an excellent case in point. This 

 author, who worked for four seasons in the 

 millponds of the Huron River, records a 

 wealth of careful observation about this 

 fish. He discusses such aspects as second- 

 ary sexual characters, habits not peculiar to 

 the breeding season, nest-building, guarding 

 of the empty nests by males, guarding the 

 eggs, protective colors of males, history of 

 the eggs and young in the nest, history of 

 the young outside the nest, and the be- 

 havior of the male while with the school. In 

 a historical chapter one need hardly make 

 the point that sound data such as these, 

 multiplied many times to include many dif- 

 ferent animals, are of profound importance 

 both during the decade of their publication 

 and for years afterwards as well. Reighard's 

 paper on Amia drives the point home! 



The paper of E. A. Andrews on the 

 breeding habits of Cambarus affinis was as 

 thorough a study of an arthropod as that 

 just described was for a vertebrate. An- 

 drews covered much the same sort of 

 observation as did Rei8;hard. In addition, 

 he added some simple biometric linear 

 measurements of the whole animal and cer- 

 tain of its parts that did much to embellish 

 his work. Biometrv was already making its 

 influence felt on ecologv and natural his- 

 torv. In England, Karl Pearson was in the 

 midst of his dynamic career, and in Amer- 

 ica. Ravmond Pearl and C. B. Davenport, 

 to be followed soon bv J. A. Harris, were 

 applying statistical methods to many kinds 



of data. Studies such as these had the 

 vital importance of forcing ecologists to 

 think in a more analytical fashion about 

 group characteristics. 



The latter point is even better made by 

 looking at two 1907 papers of S. A. Forbes. 

 This excellent naturalist of ^Vheeler's "com 

 and saleratus" belt did much for ecology 

 starting with his estimable essay. The Lake 

 as a Microcosm (p. 36). In the 1907 stud- 

 ies Forbes discussed the local distribution 

 of Illinois fishes and the bird population of 

 Illinois in autumn. In both papers the 

 reader detects careful observation, apprecia- 

 tion of the natural history of the forms 

 studied and an insistence that numbers 

 as well as names should be listed. In the 

 fish paper Forbes (1907a) develops what 

 he calls the "Coefficient of Association," de- 

 signed to show the frequency with which 

 one species is found associated with another 

 in nature. This statement took the following 

 form: 



C.A. = 



ad 



be 



where a equals the total number of collec- 

 tions to be used in the computations; b, the 

 number of collections containing the more 

 abundant of two species to be compared 

 with another; c, the number of collections 

 containing the less abundant of these 

 species, and d, the number of collections 

 each of which actually contains both species 

 together. Despite the fact that Forbes' 

 coefficient is imperfect and is not used by 

 modem workers, it did serve the important 

 function of stating a real problem and sug- 

 gesting a solution. 



In a verv real sense, htfdrobioJogy (both 

 oceanography and limnology) has devel- 

 oped as a subscience in its owti right. How- 

 ever, since we shall be referring continually 

 in this book to ecological principles derived 

 from the data of hydrobiology, and since its 

 early historical development is one and the 

 same with ecology proper, we must examine 

 its contribution to our historical analysis. 

 During the decade 1900 to 1910 many in- 

 vestigations of aquatic ecology were 

 published. We shall sample a few repre- 

 sentative studies. 



From the marine aspect Johnstone's book 

 (1908) and the papers of Ostenfeld (1908) 

 and Sumner (1910) are characteristic. 

 Johnstone's book was a competent summary 

 of modem oceanography. In the first part 



