THE SACRAMENTO SALMON. 197 



Immediately after the extrusion of a few ova, the female moves 

 away from the 'nest/ and the male takes her exact position, or some- 

 times a little down stream from it, and extrudes a small quantity of 

 milt. The milt is a milky white fluid as full of spermatozoa as blood 

 is of corpuscles. It rapidly disseminates through the water, and is 

 carried away by the current just as the ova were. Doubtless many 

 hundred spermatozoa come in contact with each ovum, though prob- 

 ably only one finds its way through the micropyle, which causes 

 fertilization. The salmon egg is too large to permit a microscopic 

 examination of the process of fertilization, though without doubt it is 

 the same as in other fishes. 



Artificial Propagation. 



Fertilization is secured at fish culture stations by expressing the 

 ova and milt simultaneously into a pan and thoroughly mixing them 

 by stirring with a feather or the fingers. Two methods of procedure 

 are in vogue among salmon culturists. 

 The one, known as the ' dry ' method, 

 consists in expressing the ova and milt 

 into a pan that has been merely rinsed 

 with water; in the other, known locally 



as the 'wet' method, about a pint of /^^ 



water is placed in the pan before the 

 spawning. A careful comparison of the 

 results has failed to show any differ- 

 ence. The ' wet ' method requires a 

 less quantity of milt, which is some- 

 times a desideratum. 



Numerous experiments were per- 

 formed testing the vitality of ova 

 and milt under various conditions, of 

 which I note the following: 



A quantity of the ordinary creek 

 water, such as was used in artificial 

 propagation, was spermatized, and a 

 portion of it used for fertilizing ova 

 at various periods after the sperma- 

 tization, in order to test the vitality 

 of spermatozoa in water. The follow- 

 ing results were obtained from one ex- 

 periment, which may be considered typical : 



