r.6 



the subject, that when the male parr has perfected his milt, the female presents 

 only the rudiments of ova. Had they arrived at maturity — were they indeed a 

 distinct species — both males and females must necessarily be complete in their 

 organisation ; the one, as well as the other, would show a corresponding breeding 

 condition. No more appropriate instance of this need be desired than is shown 

 in one of their own genus — the smallest of the migratory salmonidse — the smelt. 

 I have, at different times, examined considerable numbers of these little fish, and 

 invariably found the milt and ova in an equally advanced stage in every specimen. 

 When near the spawning time— toward the end of M.arch— the milt of the male 

 and the ova of the female are advanced, simultaneously, to that state when either 

 can be made to flow by slight abdominal pressure with the fingers. Here we have 

 a distinct species of the genus salmo, perfect, and scarcely larger than the parr, 

 at his migratory stage ; and were that parr an equally small, distinct, and perfect 

 species, it is incredible to suppose that the male could breed .and the female could 

 not ; that in short, the history of its breeding should be altogether unknown. Every 

 experiment, too, has invariably ended in proving the parr to be the young of the 

 salmon. Those now extensively carried on by the two Frenchmen, Gehin and 

 Remy. but confirm the experiments of Shaw and others. The French Govern- 

 ment has had the wisdom and patriotism to grant a sum of 30,000 francs to these 

 two men for an extensive artificial production of fish ; for the joint purposes of 

 scientific objects, and an increase of the national resources. 



In a scientific point of view, as well as in political economy, the breeding of 

 fish is of some importance ; and as many may not be aware of the facility of pro- 

 ducing fish, by manipulation, and of the enormous quantities to be so produced, 

 I may be allowed an observation or two on these points. 



Perhaps I ought, for a moment, to advert to the singular assertion of Dr. 

 Robertson, of Dunkeld, namely, that he had produced trout, through the agency 

 of the female only — I mean, by extracting the roe from the female, without subse- 

 quent fecundation — that it had vivified. If this be true, previous impregnation 

 must have taken place ; which is Dr. Robertson's theory. How comes it, then, 

 that the milt of the male, and the ova of the female, disappear at precisely the 

 same time ? If impregnation had occurred before the female's deposit, the male 

 would be void, or nearly so, of milt, at a period prior to such deposit ; which is 

 contradicted by the unanimous testimony of numberless observations. The milt 

 is not only a secretion of gradual progress, but is imperfect, until the cavity in 

 which it forms is entirely filled. This great accumulation suddenly disappears — 

 completely and at once- Is it credible to suppose that intromission produces this? 

 Eminent anatomists have, from careful examinations, come to the conclusion that, 

 as in the case of the frog, the organization of the fish is such as to render impreg- 

 nation, in utero, impossible. My own testimony must be of little value ; yet from 

 the trifling practical knowledge I possess, I believe impregnation in utcro 

 physically impracticable. If Dr. Robertson's theory be correct, it seems to me, 

 that nature has formed a superfluity in the excessive quantity of milt ; a quantity 

 easily accounted for, and necessary, on the supposition of extra uterine impregna- 



