744 REPORT OF COMMISSIONER OF FISH AND FISHERIES. [4] 



were chiefly remarkable for failure, tliougli both have their value in ten- 

 tative work. I shall not therefore burden this report with such ac- 

 counts, but confine myself to a statement of the methods and appara- 

 tus we found of assistance, and of the influence, so far as we were able 

 to observe it, of the various natural conditions affecting the develop- 

 ment of the egg. 



1. Selection of the oysters. — This is a jioint of more importance than I 

 had supposed. Even in the height of the spawning I found it necessary 

 to use care in selecting the oysters from which I was to derive the gen- 

 erative matter, and it is especially necessary to use this care with regard 

 to the males. At Fair Haven 1 have frequently hunted over thirty or 

 more oysters before finding a male with the spermatozoa in an entirely 

 satisfactory condition. The superfluous male fluid is difiicult to get rid of 

 after the eggs have been impregnated, and this difBculty is much in- 

 creased when the spermatozoa are dead or immature; but unless removed 

 they soon pollute the water. Bad eggs are of less trouble, but their 

 removal is sufficiently embarrassing to make it desirable to use only 

 those that appear entirely ripe. While experimenting on a large scale, 

 with immense numbers of eggs, as I did at Fair Haven, the temptation 

 is great, on account of the saving of time and labor, to take any and all 

 oysters without exposing the contents of the generative organs to the mi- 

 croscopic examination ; but I found by experience that it would not do to 

 trust to subsequent manipulation for the removal of unripe ova and S])er- 

 matozoa ; such a course required in the long run more time and labor than 

 the selection of good oysters would have done in the first place, and was 

 not always entirely efficacious. I think the failure of some of the experi- 

 ments, both at Beaufort and Fair Haven, was undoubtedly due, or par- 

 tially due, to neglect of these pr^'cautions. At Beaufort we were some- 

 times compelled to take inferior oysters, but at Fair Haven it was 

 possible at all times, with care, to secure a sufficient number entire- 

 ly suitable for experiment ; and if other investigators in this field 

 are located near any large oysters area they should not experience 

 any greatdifficulty in obtaining ripe animals throughout the si)awning 

 seasoD. It must be remembered that the time of spawning or the 

 ripeness of the oyster in any locality is dependent upon several condi- 

 tions, the principal being the depth and density of the water, the shal- 

 low and brackish water oysters si)awning first. I am of the opinion 

 that even those oysters from the same spot will be found to be in vari- 

 ous stages of ripeness, such having always been my experience, and, 

 consequently, it is necessary to search carefully for unfit animals, even 

 when the majority of the lot appear iu an entirely proper condition. 

 Tliis refers, of course, to an experiment on a large scale, somewhat simi- 

 lar to my own at Fair Haven, where I used the generative matter of 

 several hundred oysters nearly every day. Working on a smaller scale 

 the experimenter would naturally use sufficient caution. Throughout 

 the season, with large and small numbers of eggs under observation, 



