472 ZOOLOGY. 



tional laws. Eternal and unchanging, the orbs move in their 

 spheres precisely as they did millions of years ago. Proceeding, 

 as it were, from an invisible point endowed with life, he passes, 

 rapidly at first, through many forms, all resembling, more or 

 less, either different races of men from his own, or animals lower 

 in the scale of being ; or beings which do not now exist, though 

 they probably once did, or may at some future time. When his 

 development is imperfect, it represents then some form, resembling 

 the inferior races of men, or animals still lower in the scale of 

 being. Moreover, what is irregular in him is the regular struc- 

 ture in some other class of animals. Take, for example, the 

 webbed hand or foot occasionally found in man, constant in 

 certain animals as in the otter and beaver ; constant also in 

 the human foetus, that is, the child before birth. Take, for 

 example, the cuticular fold at the inner angle of the eye, so 

 common with the Esquimaux and Bosjesman or Hottentot (the 

 corresponding yellow races of the northern and southern hemi- 

 spheres), so rare in the European, but existing in every fcetus of 

 every race. Nor let it be forgotten that forms exist in the human 

 fcetus which have nothing human in them in the strictest sense 

 of the term ; that the fcetus of the Negro does not, as has been 

 stated, resemble the foetus of the European, but that the latter 

 resembles the former, all the more resembling the nearer they 

 are to the embryonic condition. Unity of structure, unity of 

 organization, unity of life, at the commencement of time, whether 

 measured by the organic world or by the duration of individual 

 life." This is the law. 



The relation of species to genus also merits our deepest atten- 

 tion.* 



"My first observations were made on animals low in the scale 

 of the vertebrata, on fishes, in fact. I selected, as I shall 

 presently more fully explain, the natural family of the Salmonidse, 

 as the one to which I had given most attention. In the young 

 of the true salmon I found the specific characters of all the sub- 

 families of the genus present ; that is, reel spots, dark spots of 

 several kinds, silvery scales, proportions, and a dentition iden- 

 tical. The young fish before me was, in fact, a generic animal, 

 including within it the specific characters of all the species com- 

 posing the natural family. To connect this generic animal with 

 any species, you have but to imagine the disappearance of certain 

 characters then and there present. Nothing requires to be added. 

 Take, for example, the dentition the dentition of the vomer, to 

 which M. Valenciennes attaches so much importance, and in 

 which he has endeavoured to discover the true distinguishing 



* See " Memoirs on the Philosophy of Zoology," in The Zoologist. 

 Voorst, London; and in the Lancet, 1855. E. K. 



J. Van 



