256 EEPORT OF COMMISSIONER OF FISH AND FISHERIES. 



cases and G7^ iu another, the record aflfording- no explanation of either 

 of them. It is probable that few, even of the lots indicated by the trial 

 to be fully fecundated, were quite so, since they had to be judged by 

 samples, a method that does not admit of strict accuracy. In the 

 thirty-eight lots alluded to, tlie presence of a small percentage of infe- 

 cundated eggs is certain. The inquiry naturally arises, what was the 

 cause of their failure? It cannot be traced to an insufficient supply of 

 milt; for iu two lots that were milted heavier than usual, only 97 J per 

 cent, of the eggs were fecundated, while in another lot, taken on the 

 same day and scantily milted, the percentage was 100. 



After being once manipulated, the females were placed in the watei" 

 to recover from their exhaustion, and await a second manipulation a few 

 days later, when they would yield about three hundred eggs each. The 

 rate of fecundation in these eggs was unequal. On the 1st day of No- 

 vembei all the females used before, sixty in number, yielded at a second 

 trial 16,300 eggs, and only 77^ per cent, were fecundated, while in some 

 of the subsequent lots of this kind the fecundation was complete. 



The eggs taken from those spent fish that had spawned naturally ex- 

 hibited the same inequality in their susceptibility to fecundation. I 

 think it is to be explained, not by an original defect in the egg, but by 

 the action of the water that frequently obtains access to the abdominal 

 cavity after it has been emptied of most of the eggs, and when present 

 in great quantities might be expected to exert an influence similar to that 

 which it would exert on the eggs after they had left the fish. It would 

 incite them to expansion, and they would then lose their susceptibility 

 to fecundation. A small quantity of water might remain near the vent 

 or be insufficient to overcome the viscid fluid in which the eggs swim 

 and which, while it surrounds them, prevents their absorbing water. 



From all this it would appear, first, that there are, as a general rule? 

 no defective eggs iu the ovaries of a salmon ; and, second, that when 

 she first begins to spawn, the eggs are all ripe and ready to be laid and 

 fecundated. 



There are exceptions to the first proposition. One of Ihe salmon 

 manipulated at Orland in 1871 yielded no eggs until December, when 

 it was found by dissection that, though her ovaries contained some full- 

 sized eggs, the majority of them were only partially grown, being of a 

 great variety of sizes, from nearly a quarter of an inch down to the fifti- 

 eth of an inch in diameter. These were all adherent to the ovary. 

 Unfortunately the lack of milt prevented the testing of the susceptibil. 

 ity of the full-grown eggs to fecundation. There are occasionally found 

 in a lot of healthy eggs a few that are white and opaque on issuing from 

 the fish ; and I have found them in the abdominal cavity. I can assign 

 no cause. I have also seen eggs that at the moment of leaving the fish 

 bore to the eye distinct evidence of being in an abnormal state, appa- 

 rently a stage in the process of disorganization. In some cases, although 

 the egg was of full size, the yolk and the oil-globules only appeared as 



