410 ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



during their first year of growth, much before they have at- 

 tained a marketable size. He has even seen oysters of less 

 than an inch in diameter with the sexual conditions mature. 

 It would therefore appear that the multiplication of this 

 important bivalve does not require the presence, in a park, 

 of full-grown oysters, since those of a much smaller size 

 have been proved to answer the purpose. 3 B^ March 2, 

 307. 



FATTENING OF OYSTERS. 



Professor Fraser, in a communication to the Academy of 

 Natural Sciences, in speaking on the general subject of Di- 

 alysis, suggested its application to the fattening of oysters, 

 remarking that oysters brought to the large markets are gen- 

 erally immersed for a short time in fresher water than that 

 from which they were taken, resulting in an increase of size 

 or plumpness. This, however, only lasts for a few days. At 

 the end of this time the oysters become lean again, having 

 lost the plump appearance. Dr. Fraser remarks that, al- 

 though sometimes corn meal or other substances are placed 

 upon the oysters during this operation, it can have no mate- 

 rial effect in increasing the amount of the flesh, but that the 

 increase in size is due entirely to the absorption of moisture. 

 The tissues of oysters when first taken are saturated with 

 the ocean brine, and when removed to fresh water, or that 

 which is less salt, the external liquid passes inward more rap- 

 idly than the more saline and denser elements within can es- 

 cape; the efiiect being simply to cause the oyster to swell, 

 with no increase of its virtues. When the water in which 

 the oyster is immersed is too fresh it loses its flavor. Pro- 

 fessor Fraser suggests that by immersing the oysters for 

 some days in concentrated brine, and then removing them to 

 ocean water, the plumpness Avould be gained without the 

 sacrifice of the saltness which is so agreeable to the epicure. 

 A simple method of ascertaining whether the oysters increase 

 in flesh or not Avould be to take one hundred or more from 

 a given locality on the sea-coast, and, drying them at 220"^ 

 Fahrenheit, ascertain their average weight ; after which re- 

 peat the process for the same number of like oysters after 

 being gathered and treated in the usual manner. 2 D, 442. 



