THE CHEMISTRY OF " OYSTER-FATTENINGP 85 



lusks, when irritated, produce an extremely abundant secretion of mu- 

 cus or " slime " — so much, indeed, as to sometimes render a small quan- 

 tity of water in which the animals may be confined, quite sensibly 

 gelatinous. He suggests that the change to fresh water may induce 

 such a secretion of mucus, and perhaps of carbohydrates and fats 

 as well, as would account for the increase of these substances in 

 the liquids. The observation of oyster-dealers that " water always 

 thickens the natural juices that adhere to the surface of the oyster and 

 makes it slimy," accords with Professor Conn's statement. 



If such secretion did take place, the flesh must probably have lost 

 a little protein during the floating. The estimates of absolute gain 

 and loss of weight of flesh and ingredients are based upon the assump- 

 tion that the quantity of protein was unaltered in floating. If protein 

 was given off, therefore, the estimates are wrong. But the quantity 

 of protein secreted and the consequent error must be, at most, very 

 slight. If there is an error, its effect would be to make the quantities 

 of nutrients after floating appear larger than they really were. In 

 other words, if the error were corrected, it would make the loss of 

 nutritive material in floating greater than it appears to be in the fig- 

 ures above given. 



The experiments might have been so conducted as to decide this 

 question of the exact gain and loss of weight of each material in the 

 oysters. It would have been necessary to simply take a larger num- 

 ber in each lot before and after floating, and be certain that the num- 

 ber, weight, and bulk were the same in the floated and not-floated lots 

 of each experiment. For instance, we might, in each experiment, 

 carefully select two lots of, say, a bushel each, as taken from the 

 beds ; have the number of oysters the same in each bushel, as an 

 additional assurance that the two lots were alike ; float one bushel, 

 and weigh and analyze both. A few experiments of this sort made 

 under different conditions of time, temperature, kind, and age of 

 oysters, etc., would give very reliable and valuable data. Unfortu- 

 nately, the means at my disposal did not permit so thorough experi- 

 ments. I am persuaded, however, that the results of such series of 

 trials, if they could be made — and I wish they might be — would be 

 very similar to those of the trials here reported. 



It is very interesting to note that these processes of both osmose 

 and secretion which we have been considering in the body of the 

 oyster are apparently very similar to processes which go on in our 

 own bodies — namely, those by which our food, after it is digested, 

 finds its way through the walls of the stomach and other parts of the 

 alimentary canal into the blood, to be used for nourishment. Physi- 

 ologists tell us that the passage of the digested materials through the 

 walls of the canal is in part merely a physical action, due to osmose, 

 but that it is in part dependent upon a special activity of the cells of 

 the villi. In like manner, the changes in the composition of the oys- 



