OYSTER CULTURE IN FRANCE. 627 



their vital properties. Our collaborateurs have, like our- 

 selves, obtained the best fecundations with elements which 

 have not been brought together for one or two hours after 

 their separation from the glands. 



In bringing this account to a close we will mention 

 some relative observations : i . On the influence exercised 

 by the water at different densities, in the operations with 

 which we are engaged, 2. On artificial hatching. The 

 waters employed at Verdon weighed, according to the 

 areometer, from two and a quarter to three degrees. 



At Cette we used, with success, the waters of the 

 Mediterranean, the density of which in this locality attains 

 nearly four degrees. 



In the present state of our researches it is difficult to 

 draw any conclusion from the facts which we narrate as 

 they present themselves, and especially from the two 

 which precede. It appears no less certain that, although 

 oysters cannot prepare for reproduction in salt water, the 

 same salt water may prove not unfavourable to fecundation 

 and to development. 



As regards attempts at artificial hatching, we have 

 done no more than apply the methods which are employed 

 in the similar case of the eggs of birds. The eggs of 

 oysters laid in a water kept at a uniform temperature of 20 

 degrees, are hatched after 10^ hours of incubation. 



It might, perhaps, be profitable to make researches in 

 this direction, for if methods of artificial hatching could 

 enter the domain of industry, the incubation of eggs would 

 be practicable at all times, except in stormy seasons, which 

 destroy the ova and even the larva. With our present 

 experience hatching as well as fecundation do not succeed 

 well except in warm and fine seasons. 



