PURE AND IMPURE FOODS. 



" What a Man Eats He IsP 

 Edited by C. F. Langworthy, Ph. D. 

 Author of "On Citraconic, Itaconic and Mesaconic Acids," "Fish as Food," etc. 



OYSTERS. 



Oysters and other shell fish resemble 

 meat and food fishes in general composi- 

 tion. They contain considerable pro- 

 tein and a little fat and ash in ad- 

 dition to a fairly high percentage of 

 water. Shell fish also contain a small 

 quantity of carbohydrates. Oysters are 

 the most important of the shell fish, 

 judging by the relative number consumed. 

 Speaking roughly, a quart of oysters con- 

 tains on an average about the same quan- 

 tity of actual nutritive substance as a quart 

 of milk, or % of a pound of beef, or 2 

 pounds of fresh codfish, or a pound of 

 bread. But while the weight of actual nu- 

 triment in the different quantities of food 

 materials named is nearly the same, the 

 kind is widely different. That of the lean 

 meat of codfish consists mostly of pro- 

 tein, the substance whose principal function 

 is to make or repair blood, muscle, tendon, 

 bone, brain and other nitrogenous tissues. 

 That of bread contains considerable pro- 

 tein, but a much larger proportion of 

 starch, with a little fat and other com- 

 pounds which serve the body as fuel and 

 supply it with heat and muscular power. 

 The nutritive substance of oysters contains 

 considerable protein and fuel ingredients. 

 Oysters come nearer to milk than almost 

 any other common food material as re- 

 gards both the amounts and the relative 

 proportions of nutrients. 



Apparently as the oyster grows older, at 

 least up to a certain time, not only do 

 the proportions of flesh and liquids increase 

 more rapidly than the shells, but the pro- 

 portion of nutrients in the edible portion 

 increases also; 'that is to say, 100 pounds 

 of young oysters in the shell appear to con- 

 tain less of flesh and of liquids than 100 

 pounds of older ones, and when both have 

 been shucked a pound of shell contents 

 from the older oysters would contain more 

 nutriment than a pound from the younger. 



Considering the edible portion of the 

 oyster, after it has been removed from the 

 shell, the difference in different specimens 

 is much greater than is commonly sup- 

 posed. This is apparent when a compari- 

 son is made of either the meat or the 

 liquor of different specimens, or the whole 

 edible portion, the meat and liquor together. 

 The percentage of water in the edible por- 

 tion of different specimens of oysters 

 which were analyzed in experiments con- 

 ducted for the U. S. Fish Commission var- 

 ied from about 83.4 to 91.4 per cent, and 



averaged 87.3 per cent. This makes the 

 amounts of water-free substance, i. e., act- 

 ually nutritive ingredients, vary from 16.6 

 to 8.6 and average 12.7 per cent, of the 

 whole weight of the shell contents. In 

 other words, the nutritive material in a 

 quart of shell contents (solids) varied 

 from 23-4 to 51-3 ounces. 



With oysters, long clams, ancfr round 

 clams in the shell there is naturally a large 

 percentage of waste, as the shell is a large 

 portion of the total weight. The average 

 of 34 specimens of oysters in the shell, for 

 instance, shows only 2.2, per cent of actual 

 nutrients. Clams and mussels show a 

 somewhat higher percentage. 



Where these various shell fish are bought 

 as solids, that is, removed from the shell, 

 a comparatively high price is usually paid. 

 When they are bought in the shell, there 

 is a large percentage of waste. The conclu- 

 sion is therefore warranted that, from a pe- 

 cuniary standpoint, oysters are not the most 

 economical of foods for the consumer. On 

 the other hand, they have a useful place 

 in the diet in helping to supply the variety 

 which is apparently needed to insure the 

 best workings of the digestive system. 

 Often flavor has value which can not be 

 estimated in dollars and cents. 



It is a common practice of oyster dealers, 

 instead of selling the oysters in the con- 

 dition in which they are taken from the 

 beds in salt water, to place them for a time 

 in fresh or brackish water, in order, as the 

 oystermen say, to fatten them, the oper- 

 ation being also called floating or lay- 

 ing out. By this process the oyster ac- 

 quires plumpness and rotundity, and its 

 bulk and weight are so increased as to ma- 

 terially increase its selling value. The be- 

 lief is common among oystermen that this 

 fattening is due to actual gain of flesh and 

 fat and that the nutritive value of the 

 oyster is increased by the process. They 

 find that the oysters fatten much more 

 quickly in fresh than in brackish water. 

 Warmth is so favorable to the process, that 

 it is said to be sometimes found profitable 

 to warm artificially the water in which the 

 oysters are floated. Although oysters are 

 generally floated in the shell, the same ef- 

 fect is commonly obtained by adding fresh 

 water to the oysters after they have been 

 taken out of the shell. Oysters lose much 

 of their salty flavor in floating, and. it is 

 a common experience of oystermen that if 

 the fattened oysters are left too long on 

 the floats they become lean again. It does 



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