IX THE HISTORY AND SCOPE OF ZOOLOGY 355 



zoologist goes to the native land of an interesting 

 animal, there to study it as fully as possible. The 

 most important of these voyages has been that of W. 

 H. Caldwell of Cambridge to Australia (1885-1886) for 

 the purpose of studying the embryology of the Mono- 

 trema. and of Ceratodus, the fish-like Dipnoon, which 

 has resulted in the discovery that the Monotrema are 

 oviparous. Similarly Adam Sedgwick proceeded to 

 the Cape in order to study Peripatus, Bateson to the 

 coast of Maryland to study Balanoglossus, and the 

 brothers Sarassin to Ceylon to investigate the em- 

 bryology of the Ccecilia. 



The task of the zoologist has changed and devel- 

 oped in every succeeding period. Pure morphography 

 has long ceased to be a chief line of research ; and 

 now even the preoccupation produced by the addition 

 to it of the study of cellular Embryology is about to 

 undergo a modification by the demand for knowledge 

 of the facts of heredity and adaptation in greatly 

 extended detail. 





 ZOO-MECHANICS, ZOO-PHYSICS, ZOO-CHEMISTRY 



The development of that knowledge of the struc- 

 ture of the human body, and of the chemical and 

 physical processes going on in it, which is necessary 

 for the purposes of the medical art, forms a distinct 

 history, which has both influenced and been influenced 

 by that of other branches of Zoology. The study of 

 the structure and composition of the body of man and 

 of the animals nearest to him was until fifty years ago 



