LXXIV REPORT OF COMMISSIONER OE FISH AND FlSHKRtES. 



The following table shows the percentage of impregnation in each lot: 



On December 8 the experiment was repeated with, if possible, more 

 care than on the previous occasion. It was carried further, to deter- 

 mine the point at which absolute loss of vitality would take place. 

 The following table shows the result, the temperature of the water 

 being 35.5°: 



It will bo seen that the eggs fertilized 1J minutes after water was added to the milt showed but 2 

 per cent alive, while those atreoted bj the next period, a quarter of a minute later, showed 42 per oent. 

 Although great care w as taken to avoid mistakes, it Is evident that there was one In this case, or that 

 something in the pan caused the death of a great number of those eggs. 



It frequently occurs that large numbers of eggs are lost during the 

 latter part of the season, owing to the scarcity or entire absence of 

 males when large numbers of ripe females are taken. To overcome this 

 difficulty, experiments were conducted to determine how long milt and 

 eggs could be curried alive separately and then fertilized. The milt of 

 5 males was taken in a vial which had been rendered chemically clean 

 and dry. Great care was exercised in taking the milt, and to avoid 

 the mixture of water, excrement, or other foreign substances, the 

 mouth of the vial being held up close to the vent of the fish, and only 

 such portion taken as came in a stream. The vial was then tightly 

 corked and placed in running water in a pan, so as to secure a tempera- 

 ture as nearly that of the fish as possible. This milt was taken at 

 10.45 a. m. on December 4. On the following day, at the same hour, a 

 small amount of eggs was fertilized with this milt. An examination 

 showed that the percentage of impregnation was as complete as would 

 naturally bo the case with fresh-taken milt. A series of experiments 

 of the same character was continued for several days, the eggs being 

 kept in clean pans in running water, light being excluded. All the 

 milt was treated as the first lot, precautions being taken not to let 

 water enter the vials when the corks were removed. 



The following table is self-explanatory. In making the counts, all 

 eggs with ruptured yolk-sacs or those destitute of germinal discs were 

 disregarded, the object being to determine the percentage of impreg- 

 nation. The examinations were as carefully made as practicable, 100 

 eggs impregnated and unimpregnated being counted for each lot below 

 referred to. 



