Comparative Morphology of Chordates 



What? Whence? Whither? 



Natural Science, of which Comparative Morphology is a field, 

 comprises man's endeavors to know and understand his environment, 

 even to the remotest stars, and himself — if it is possible for anything 

 to "understand itself"? For long ages past, his curious mind has been 

 perplexed by three questions : What am I ? Whence came I ? Where am 

 I going? Comparative Morphology has given a partial answer to the 

 first question. Man possesses the essential peculiarities of all animals 

 from Ameba upward. His embryonic notochord, pharyngeal pouches, 

 and hollow dorsal neural tube make him a chordate. Hair and mam- 

 mary glands make him a mammal. Nails on the digits, an opposable 

 thumb, and otherwise a conspicuous lack of highly specialized organs 

 make him a primate. Numerous trivial anatomic characteristics dis- 

 tinguish him from apes. His preeminent peculiarity is his capacity for 

 acting constructively upon his environment. This action depends upon 

 his possession of a brain whose neurons are so linked together as to 

 make possible reactions which manifest mental faculties such as we 

 designate as "purpose," "imagination," "intelligence." At this point 

 our knowledge stops. The relation of mental faculties or "mind" to 

 nervous structures is a baffling problem. Such a simple statement as 

 "I made up my mind to cut down the tree" seems to imply that a 

 human individual is a trinity of entities. There is an "I" that "makes 

 up" something which it calls its "mind," and the tree is cut down by 

 the body. Comparative Morphology has learned much about the body. 

 The psychologist describes states of mind and their relations to the 

 sensory nervous impulses which precede them and the motor impulses 

 consequent upon them. The philosopher contemplates the whole 

 trinity in a brave effort to make it understand itself. He offers us 

 numerous philosophies from which we may choose according to our 

 individual tastes, but no one of them seems to give us anything more 

 intelligible or satisfying than the elemental "I am that I am." 



To the second question — "Whence came I?" — Comparative Mor- 

 phology has given an answer whose correctness cannot reasonably be 

 questioned. No man should feel it ignominious to have come from a 

 long line of subhuman ancestors. Far from causing him to feel belittled, 

 knowledge of it should give him higher esteem and more consideration 

 for his fellow vertebrates. In some matters of behavior, he could profit 

 from their example. If the hundreds of millions of years of vertebrate 

 history could be contracted to the dimensions of a modern moving 

 picture, its appearance on the screen would be a mighty spectacle, 

 surpassing in its dramatic power and rich in inspiration to us who seem 



