ADAPTATION AND INHERITANCE IN THE LIGHT OF MOD- 

 ERN EXPERIMENTAL INVESTIGATION.^ 



By Paul Kammerer, Vienna. 



[With 8 plates.] 



At the opening of the eighth session of the International Zoological 

 Congress at Graz, in August, 1910, the Graz Tageblatt contained a 

 leading article by Prof. Franz von Wagner, of the University of Graz, 

 the introduction of wliich ended as follows: 



Zoology has expanded tremendously since the publication of Darwin's works, 

 both in breadth and profoundness, and the frail seedling of his day has developed 

 into a sturdy tree with many branches. None of the newer fields of the scientific 

 study of animals illustrate this more convincingly than the steady progress which has 

 been made in recent years iu Experimental Zoology. This, as a special study, in the 

 systematic development of methods, has attacked not only the problem of the devel- 

 opment of organic form, but has even attempted to solve the riddle of life, striving at 

 the same time to impress upon biology, as far as possible, the stamp of an exact science. 

 It is certainly not through chance that this phase of modern zoology will receive a 

 great amount of attention in the congress at Graz. 



During the sessions of the congress, many otlicr individuals ex- 

 pressed similar opinions, among whom a goodly number presented 

 papers or took part in the discussions. Of these there come to mind 

 men of such note as Appelof, Gadow, and Plate, wdio emphasized 

 the importance and absolute necessity of basic experimentation. 

 Indeed, we dare not any longer be satisfied simply to observe final 

 facts in nature as they present themselves completed to the ol)servcr 

 and merely incorporate this mass of isolated data in a mountain of 

 knowledge, but we must soelc the causes wliich imderlie these phe- 

 nomena. This can not be accomplished by mere descriptions of those 

 final products and a comparison of them, but b}'- experimental analy- 

 sis. In this, the factors winch appear to us to be responsible for a 

 definite phenomenon are isolated and allowed to react, or they are 

 completel}^ suppressed; that is, the conditions found in nature are 

 artificially changed in many ways. These are the same methods 

 which have always been applied in chemistry and physics, the so- 



' \ lecture delivered Dec. 14, 1910, before the Scientific Society of Berlin. Translated by permission 

 from Himmel und Erdc, Berlin, June, 1911, pp. 385-395; July, 443-457. 



85360°— SM 1912 28 421 



