SALMON. 47 



of the tail, thus alternately digging, depositing, and cover- 

 ing ova, until the process is completed by the laying 

 of the "whole mass, an operation Avhich generally occupies 

 three or four days. In the course of these experiments, 

 it has been ascertained that the milt of a single male Parr, 

 whose entire weight may not exceed one and a half ounce, is 

 capable, when confined in a small stream, of effectually im- 

 pregnating all the ova of a very large female Salmon. On 

 the spawn first quitting the body of the female, it is found to 

 be enveloped in a thin coating of viscous matter, which the 

 action of the water does not immediately destroy, but which 

 continues to admit of a partial adherence to the gravel at the 

 bottom of the spawning bed, where the ova receives the ne- 

 cessary fecundation of the milt, and are afterwards covered 

 with gravel by the instinctive efforts of the female parent, in 

 the manner above described. 



" How long these ova will remain excluded from the body 

 of the female, and yet continue capable of receiving with 

 effect the fecundating action of the milt, I have not hitherto 

 ascertained. I have, however, made several experiments on 

 the ova after the parent had been a considerable time dead, 

 and removed from the*river. In one particular instance, the 

 female had been dead for nearly two hours without the vital 

 principle of the spawn being in the least degree affected, 

 as, on being afterwards placed in water, and the milt of a living 

 male poured upon it, it exhibited within the usual period the 

 same healthy and progressing vivification, under a similar 

 temperature, as that taken and impregnated the moment it 

 quitted the body of the living parent. I have merely stated 

 this fact as being in part corroborative, so far as relates to the 

 Salmon, of similar experiments made by M. Jacobi on indivi- 

 duals of the same genus. 



" The extraordinary nature of the experiments made with 

 the Parr and Salmon, I have no doubt will tend to stagger 



