1916] Introduciion ix 



organism which is deseribablp only in terms of structure and function? 

 To make tliis description is fully as important and essential for 

 understanding the relations maintained between organisms and their 

 environments as anything an eeologist — as such — can reveal. 



"Why is the eopepod Calanus finmarchicus typically more abundant 

 in the San Diego region than its near relative Emalanus elnngatus? 

 Why is Sagitta enflata captured in the San Diego region only within 

 ten fathoms of the surface, while S. lyra is seldom captured above one 

 hundred fathoms? "Why does the etenophore Plrurohrachia harhci 

 increase in abundance on the surface as the temperature of the water 

 increases from 16° C to 20° C, and why have specimens exceeding nine 

 millimeters in height never been taken from water exceeding 17° C, 

 although they occur abundantly in colder water ? As the temperature 

 of the water increases between 15° C and 20° C, why are the zooids 

 of the sexual generation of Salpa democratica obtained from the sur- 

 face in decreasing numbers while those of the asexual generation are 

 obtained in increasing numbers? Such problems are as fundamentally 

 morphological and physiological as they are ecological, but most marine 

 biological institutions almost completely ignore them. They are 

 admittedly outside their chosen lines of research. Yet no marine 

 organism can be well nnderstood until many problems such as these 

 are solved. 



What of it? What value has the fact that four hundred individuals 

 of a particular species were obtained when the temperature of the 

 water was 20° C, while only one hundred were obtained when it was 

 15° C? May it not have been a mere coincidence due to the effect 

 of random sampling? Why, then, waste time tabulating data when 

 they apparently concern facts of no importance in the life of the species 

 involved ? 



These questions carry the .subtle implication that the value of 

 facts can be predicted in advance of their observation ; that, unless the 

 bearing of certain classes of facts upon some dominant theory can 

 be foreseen, it is foolish to study them. Theories of evolution, heredity, 

 variation, adaptation, and selection must, of course, be formulated 

 before they can be proved or disproved. But nothing is more certain 

 than that they ought to be formulated in consequence of as well as in 

 preparation for inve.stigations. Otherwise induction would be replaced 

 by deduction and then no observation would be worth while unless the 

 facts which it revealed were first deduced from theory. 



