178 BIOLOGICAL LECTURES. 



Of course these would not be hereditary changes; on which 

 account, the essential results of these experiments could only 

 be utilized in explaining individual variations with reference to 

 their representing "reversions" or "monstrosities." Hence 

 it would be of greater importance to ascertain to what extent 

 after artificial local changes in an embryo, changes make their 

 appearance in other organs — no matter whether these bear 

 functional correlations to the affected regions or not — since 

 in the case of the same primary or inherited change the 

 secondary changes would then also be "inherited." More- 

 over, by raising animals that are born without fore limbs or 

 have been deprived of them, it may be possible to ascertain to 

 what extent such animals, being compelled from the first to 

 adopt a method of locomotion, like jumping, which is foreign 

 to their species, are nevertheless able by direct adaptation to 

 this mode of progression, to develop the requisite proportions 

 in the length of the skeletal parts and in the size of the lever- 

 arms of the muscles, and whether in these respects Lamarck's 

 theory is confirmed or refuted. 



In the introduction to his MorpJiologiscJies JaJirbiicJi Carl 

 Gegenbaur gave expression to the following words full of 

 insight : " Indeed the time will come when morphology, too, 

 will be conscious of the mutability of its aims and aspirations 

 and when other problems and methods will take the place of 

 those with which we busy ourselves at present." This new 

 end is that of developmental mechanics — the investigation of 

 the causes of the forms of organisms. 



But it will be a long time before it takes the place of "the 

 aim " of morphology. In the sense of the comparative anato- 

 mist, this can only come about when this science has reached 

 the measure of its possible perfection. In the last instance 

 both tendencies have the same aim and it is through coopera- 

 tion that an approach to this aim will be most facilitated. 



We must also define our position with respect to Physiology. 

 This science in its fullest sense embraces all the fimctiojis of 

 life. Developmental mechanics represents an integral part of 

 this science, and after it has reached its development it will be 

 the largest and most essential part. But alongside of human 



