BULLETIN OF THE UNITED STATES PISH COMMISSION. 323 



We would add, in conclusion, that the generative elements may be 

 preserved for some hours, without being brought into contact, and not 

 lose any of their vital properties. Our collaborators have obtained the 

 best results when the generative products were not mixed together for 

 one or two hours after they were removed from the glands. 



We will close this part of our essay with allusions to some observa- 

 tions relative to, first, the influence apparently exercised by the den- 

 sity of the water on the process of fertilization; secondly, artificial incu- 

 bation. The water employed at Verdon had a density of about two 

 and a quarter to three degrees, measured by the hydrometer for an in- 

 dicated specific gravity of about 1.014 to 1.020 of Baume's scale, the 

 one probably used. — Tr.] 



At Cette, the waters of the Mediterranean were successfully used;: 

 the specific gravity in this case was nearly 4 degrees [or nearly 1.027]. 



In the present condition of our researches it is difficult to reach any 

 conclusion in regard to the facts just recorded, particularly the two pre- 

 ceding. It does not seem any the less certain that if the oysters will 

 not be able to become sexually active in very saline waters, it does not 

 appear that such waters are inimical to fertilization and development. 

 [This was not the experience of the translator with the spawn of the 

 American oyster. It was found in fact that water of a markedly higher 

 specific gravity than that from which the spawning adults was taken 

 was injurious, especially to the milt. — Tr.] 



In respect to the attempts at artificial incubation, we would say that 

 we have employed [temperature] methods similar to those used in incubat- 

 ing birds' eggs. The eggs of the oysters placed in water maintained at 

 a uniform temperature of 20° C. [68° F.J were hatched in six and a half 

 hours. It would be profitable to make experiments in this direction j 

 for, if the method of artificial incubation is successful as applied in- 

 dustrially, it would be carried on at all times, except during cold, stormy 

 weather, which kills both the eggs as well as the larvse. With our pres- 

 ent processes the incubation as well as the fertilization are not very 

 successful, except when the weather is warm and fair. 



APPLICATION OF ARTIFICIAL FECUNDATION. 



Is it necessary to have recourse to the economy of artificial methods,, 

 in view of the evidence in favor of its advantages, opening up, as it 

 does, a new field in the ostracultural industry? 



The Portuguese oyster is endowed with surprising fertility. * If all of 



* A cubic centimetre of ovary yields : 



Ova. 



By the method of dissociation 2, 500, 000 



By the method of section .' 5,200,000 



Total 7,700,000 



(Mean, 3,850,000.) 



The volume of the ovary of an oyster of medium size varies between 6 and 8 cubie 



