fishes. -1791 



is as yet known respecting the river fish called parr was known to 

 Willoughby ; even the extraordinary fact that in the female parr the 

 ovaria remain stationary, whilst in the males the milts at certain times 

 become excessively developed. This antagonism in the character of 

 the young has no counterpart, in so far as I know, in natural history. 

 • But a still more extraordinary fact, though not so well determined as 

 the preceding, was also known to Willoughby. With this milt of the 

 male parr the ova of a salmon 40 lbs. in weight may be fecundated, 

 whilst the parr itself does not weigh more than 3 or 4 ounces. Now, 

 there is nothing like this in natural history, and the fact stands alone 

 in singularity. Reflecting on these curious facts in the history of the 

 parr, and on others connected with its natural history, I have sometimes 

 fancied that as the parr is a generic animal apparently, upon whose 

 specific form naturalists are not yet agreed, may it not be, that being 

 the product of a generic animal which has not attained a specific 

 form, it may never attain that condition, but remain in this aborted 

 state, a type merely of the salmon kind. In the case of the parr, if 

 this idea be correct, the female remains barren, the male becomes 

 productive: possibly in the great range of the zoological world there 

 may be instances of the contrary, though unknown to me ; or it may 

 happen, as a law of nature, that the generic animal of both sexes may 

 grow up unaltered and be productive, the specific forms not appear- 

 ing in the existing order of things. These are but speculations it is 

 true, but they are speculations supported by laws which hitherto have 

 been, and still are, but imperfectly understood. 



I here subjoin a single remark, lest it be supposed that I believe in 

 the reality of species. 



Species are only real in so far as regards man's observing powers : 

 they seem to form no part of Natures scheme or plan, which obviously 

 fills up all gaps, leaving no link deficient in the great chain. A serial 

 unity connects all, the past, the present, and the future. Those who 

 fancy that gaps exist mistake merely a deficiency in their own know- 

 ledge for a part of Nature's scheme. The transmutation of one species 

 into another I do not believe in, any more than in the three or four 

 successive creations of Cuvier. Unless we are prepared to adopt the 

 doctrine of chance, there can exist only one creative idea, and conse- 

 quently one creation. The theological doctrine of Socrates, worked 

 into a system by Philo-Judseus and his followers of "the final 

 cause" school, applies merely to simple mechanical laws of obvious 

 signification and application : it has nothing to do with the great 

 laws of life ; the laws of formation and deformation ; the laws of 



