74G REPORT OF COMMISSIONER OF FISH AND FISHERIES. [6] 



getting rid of the mantle, gills, digestive tract, and fragments of the 

 muscle is well bestowed.. There is but little danger of an insufficient 

 number of eggs being secured while the presence of fragments of the 

 organs just mentioned, due to hesitancy in using the scissors and sac- 

 rificing large portions of the ovaries or testes, exerts a very deleterious 

 influence upon the future development of the egg. 



As soon as the generative organs of the male are removed they should 

 be washed out in salt water. It is not advisable to defer this action 

 for any considerable time and consequently only a few oysters should 

 be treated. The spermatozoa soon dies if left exposed to the air and I 

 account for the large number of males with dead cells which I noticed 

 at Fair Haven, by my non observance on several occasions of this i)re- 

 caution. I was in the habit, at first, of opening thirty or forty oysters 

 and removing the generative organs of all, before washing out the cells. 

 As this required considerable time, and as at first I did not select the 

 males for treatment before removing the eggs from the females, many 

 of the difficulties I exi^erienced indisposing of superfluous spermatozoa, 

 and in securing thorough impregnation of the eggs, are due, probably to 

 the above cause. With the females it is, so far as my exi)erieuce goes, 

 not necessary to use so much care. The principal precaution to be taken 

 is in bringing the ova and spermatozoa in contact as soon as possible 

 after the former have been exposed to the water. As Dr. Brooks points 

 out, the eggs soon disintegrate after they are placed in the water if they 

 are not attacked by the spermatozoa. To sum up, it is advisable to 

 use a moderate number of oysters of both sexes, not to be over particu- 

 lar in securing the contents of the generative organs, to treat the males 

 tinst and supply the spermatozoa with water as soon as possible, and to 

 bring the two fluids in contact immediately after the eggs have been 

 washed out of the ovaries. Ten or fifteen minutes should be the maxi- 

 mum time of the operation. Though the observance of these points 

 precludes, to a certain extent, the manipulation of large numbers of 

 oysters by one person, yet, so far as my experience goes, it seems essen- 

 tial to success. In the experiments conducted on a small scale, when I 

 used care in all these particulars, I obtained proportionately much better 

 results than when working on a large scale and using a hundred or 

 more oysters; in the former case to accomplish the object 1 had in view 

 every care was necessary; in the latter I sacrificed something to the 

 supposed necessity of obtaining a very large number of fertilized eggs 

 every day; but, after considerable experience with both methods, I 

 am now convinced that a few oysters and eggs, carefully treated, will 

 produce a larger number of embryos than when the number of oysters 

 is so great as to preclude the observance of the most minute precau- 

 tions. 



The most satisfactory results were obtained when the two fluids, 

 having been well mixed together and the fragments of mantles, gills, 

 and organs allowed to settle, the contents of the tumbler were poured 



