336 REPORT OF COMMISSIONER OF FISH AND FISHERIES. 

 FATTENING, PLUMPING, FLOATING. 



As has been frequently pointed out, the so-called "fattening" of 

 oysters for a short time previous to sending them to market is not a 

 fattening process at all, but is a device of the trade to give to the 

 oysters an illusive ai)pearance of plumpness. It adds nothing whatever 

 to the nutritive qualities of the oyster, but on the contrary injures its 

 flavor and extracts certain of its nutritious ingredients. However, as 

 long as the i)ublic desire such oysters the dealers can not be blamed for 

 supplying thera. 



The process of plumping consists in changing oysters from denser to 

 less dense water, causing an interchange of fluids through the walls of 

 the animal, the denser fluids in the tissues passing slowly outward, the 

 less saline water in which the animal is immersed passing more rapidly 

 inward. The net result is to cause a swelling of the tissues by an 

 increase in the fluid contents, in much the same manner as a dry 

 sponge swells when moistened. The oysters are not usually placed in 

 absolutely fresh water, which would kill them if exposed too long, 

 but in fresher than that in which they have been living. The fluids 

 which have passed out from the tissues carry with them salts and some 

 fats, chemical experiment showing that the oyster, although larger after 

 plumping, has lost 13 j)er cent of its original nutritious substances, 

 protein, fats, carbohydrates, and mineral salts. Sufiicient water will be 

 taken up, however, to increase the total weight of the oyster from 12 to 

 20 per cent. The same result is produced by i)lacing the oysters in fresh 

 water after they have been removed from the shell. It will be seen that 

 what the oysters have gained is simply water, of no value as food. 



If the living oysters are left too long on the floats they will again 

 become "lean," leaner than before, in fact, owing to the state of equi- 

 librium which is finally established between the density of the juices 

 within the tissues and without. If oysters are taken from brackish 

 water to that which is considerably more saline they become shrunken, 

 tough, and leathery, owing to the converse process to that of plumping. 



Various forms of floats are used. One of the simplest consists of 

 trays 8 feet by 1(5 feet by 2 feet deep, with perforated bottoms, these 

 being raised from the water for filling and emptying by means of a chain 

 attached to each corner and a pair of windlasses supported upon piles. 



"While not harmful in itself it may be well in this connection to sound 

 a word of warning. Oysters may, and no doubt sometimes do, consume 

 pathogenic bacteria, or disease germs, with their food; and such germs, 

 transferred to the human economy with vitality unimpaired may upon 

 occasions have serious results. Care should be exercised to construct 

 the floats in such places as are free from the contaminating influences 

 of sewer discharge and other sources of pollution. 



In France the oysters are subjected to a true fattening process in 

 inclosed ponds or claires, their flavor and appearance being much 

 improved thereby. 



