•ATKINS THE SALMON AND ITS ARTIFICIAL CULTURE. 257 



a small body of colored matter floating iu tlie transparent fluid that 

 filled the outer shell. This was the case with eggs found in salmon late 

 in the winter and iu the spring, and 1 thought it proceeded from a rup- 

 ture or shrinking of the yolk membrane of an egg originally healthy. 

 Some eggs of this character were taken with healthy ones from a living 

 fish at the spawning season, and I have found them to abound iu fish 

 that had been a short time dead. This, in liict, appears to be the ordi- 

 nary course of an egg that remains too long iu the fish. It is not unlikely 

 that there are imperfections o^' other kinds than those mentioned, that 

 render the affected eggs incapable of fecundation under the most favor- 

 able circumstances. On the other hand, eggs that are iu perfect condi- 

 tion on issuing from the fish may fail from a variety of causes. Water 

 may reach them and lie in contact with them too long before the milt 

 is applied ; the milt itself may have lost its power through the influence 

 of water or air. Further, it is possible that iu some cases the milt is 

 originally inert, or becomes so while yet in the spermaries of the salmon. 

 The latter might easily occur through the influence of water entering 

 by the vent. In manipulating males that have been used once or ofteuer 

 before, a good deal of water is sometimes pressed out first, but the milt 

 that follows it appears to be efficient. Without continuing these spec- 

 ulations further, I will state the result of several experiments on the 

 fecundation of the eggs. 



4. — THE FECUNDATION OF EGGS IN LARGE OR SMALL MASSES, AND 

 WITH OR WITHOUT STIRRING. 



JExperimentl. — Lot 25, containing 3,800 eggs, was milted as usual, was 

 then watered and allowed to stand during absorption in one pan without 

 any stirring; (the pans used in all cases were circular in shape, and 11^ 

 inches iu diameter ; these eggs, therefore, lay about two deep on the 

 bottom of the pan;) fecundation 40 per cent. Lot 26, containing 7,000 

 eggs, was stirred five minutes and underwent absorption in three pans ; 

 (being 2,533 per pan ;) fecundation 100 per cent. Lot 30, containing 

 7,000 eggs, stirred and set in one pan ; fecundation 97i per cent. Lot 

 31, 13,000 eggs, milt scanty, stirred two minutes and a half, then watered 

 heavily and set iu three pans; fecundation 100 per cent. Lot 33, con- 

 taing 7,000 eggs, set iu one pan; fecundation 100 per cent. The conclu- 

 sion drawn from these results is that it makes little or no difference 

 whether the eggs are treated iu large or small masses, but that it is 

 important that they should be stirred. I suppose that \vheu the eggs 

 lie quietly in a mass just as they were taken from the fish, even though 

 they be covered with water, the viscid fluid that envelops f-hem wards 

 off, not only the water, but also the spermatozoids of the milt, until the 

 latter have become inert. I have observed with certainty that the fluid 

 referred to seriously hinders thip. absorption of water, and prolongs the 

 process for sometimes an hour beyond the usual time, which is twenty 

 minutes. Stirring assists both the water and milt to penetrate to the 



egg. 



S. Mis. 74 17 



