804 REPORT OF COMMISSIONER OF FISH AND FISHERIES. 
4. EFFECT OF OSMOSE UPON THE CONSTITUENTS OF OYSTERS. 
CHANGES IN COMPOSITION IN THE PROCESS OF FLOATING, 
IE, REMOVAL FROM SALT TO BRACKISH OR FRESH WATER. 
It is a common practice of oyster dealers, instead of selling the 
oysters in the condition in which they are taken from the beds in salt 
water, to first place them for a time (forty-eight hours, more or less) in 
fresh or brackish water, in order, as the oystermen say, to “ fatten ” them, 
the operation being called “ floating” or “laying out.” By this process 
the body of the oyster acquires such a plumpness and rotundity, and 
its bulk and weight are so increased, as to materially increase its selling 
value. 
The study of this matter has a scientific as well as practical interest. 
It is commonly assumed that the passage of the digested materials 
through the walls of the alimentary canal in the bodies of animals is 
in large part due to osmose or dialysis and that the operation of this 
physical law is very common in living organisms. The quantitative 
study of the chemical changes involved in these processes is generally 
rendered difficult or impossible by the very fact of their going on in 
living bodies where the application of chemical analysis is impossible. 
An opportunity is, however, given in the case of the oyster. 
The following experiments were made with oysters supplied by Mr. 
F. T. Lane, of New Haven, Connecticut, for whose courteous aid, as well 
in furnishing the specimens as in giving useful information, I take this 
occasion to express my thanks. 
The oysters had been brought from the James and Potomac Rivers 
and “planted” in the beds in New Haven harbor (Long Island Sound) 
in April, 1881, and were taken for analysis in the following November. 
Two series of experiments were made. The plan of each consisted 
in analyzing two specimens, both of which had been taken from the 
same bed at the same time, but one had been “ floated” while the other 
had not. The first specimen was selected from a boat-load as they 
were taken from the salt water, and the second from the same lot after 
they had been “floated” in the usual way in brackish water for forty- 
eight hours. The separations and weighiugof shells, flesh, liquor, etc., 
and the analyses of flesh and liquors, were made as described in the 
chapter on methods of analysis. It will suffice to say here briefly that 
the specimens were weighed as received at the laboratory, the shell 
contents were then taken out and the shells, flesh (body or solid portion), 
and liquids (liquid portion) weighed separately. The whole weight, less 
the sum of the weights of shells, flesh, and liquids, gave the amount of 
loss in the preparation for analysis, which loss was doubtless, for the 
most part, adhering water, though a part must, of course, have been 
due to evaporation. The statistics of the weights of the constituents 
and of the whole specimens are given in Table 37*. 
