THE INTERPRETER II9 



dial germ of a man, a dog, a bird, a fish, a beetle, a 

 snail, and a polyp being in no essentially structural 

 respects distinguishable. Like all other vertebrates, 

 the Primates pass through a period of embryonic de- 

 velopment, in which the resemblances to one another 

 are so closely the same both in outward and inward 

 form and essentials of structure 



that the differences between them are inconsiderable, 

 while, in their subsequent course, they diverge more 

 and more widely from one another. And it is a gen- 

 eral law, that the more closely any animals resemble 

 one another in adult structure, the longer and the 

 more intimately do their embryos resemble one an- 

 other ; so that, for example, the embryos of a Snake 

 and of a Lizard remain like one another longer than 

 do those of a Snake and of a Bird ; and the embryos 

 of a Dog and of a Cat remain like one another for a 

 far longer period than do those of a Dog and of a 

 Bird, or of a Dog and an Opossum, or even than those 

 of a Dog and a Monkey. 



Thus the study of development affords a clear test 

 of closeness of structural affinity, and one turns with 

 impatience to inquire what results are yielded by the 

 study of the development of Man, Is he something 

 apart ? Does he originate in a totally different way 

 from Dog, Bird, Frog, and Fish, thus justifying those 

 who assert him to have no place in nature and no real 

 affinity with the lower world of animal life ? Or 

 does he originate in a similar germ, pass through the 

 same slow and gradually progressive modification — 

 depend upon the same contrivances for protection and 

 nutrition, and finally enter the world by the help of the 

 same mechanism ? The reply is not doubtful for a 

 moment, and has not been doubtful any time these 



