SIXTEENTH ANNUAL MEETING. 45 



contains the nutritive ingredients or " nutrients." These may 

 be divided into four classes: (i) Protein compounds, the so- 

 called " fleshformers " which contain nitrogen; (2) fatty sub- 

 stances, classed as Fats; (3) Carbohydrates; (4) Mineral Salts.* 

 These constituents of the flesh of oysters have been but little 

 studied. It is customary to assume them to be similar to the 

 corresponding compounds of other food-materials, but very prob- 

 ably the differences, if known, might prove to be important. 

 The mineral matters especially which are very large in amount, 

 appear to include considerable of the salts of sea-water. Of the 

 nature of the ingredients of the liquids but little is known. They 

 consist mainly of water and salts and the amounts of their in- 

 gredients which are here reckoned as protein, fats and car- 

 bohydrates are very small, so that whatever error there may be 

 in classing them with the ordinary nutrients of food, it will not 

 very seriously affect the estimates of nutritive values. 



GERERAL RESULTS OF THE EXPERIMENTS. 



During the sojourn in brackish water both the flesh (body) 

 and the liquid portion of the shell-contents of the oysters suf- 

 fered more or less alteration in composition. In order to show 

 clearly what the principal changes as shown by the chemical 

 analysis were, some statistics may perhaps be permissible here. 



CHANGES IN THE COMPOSITION OF THE FLESH (bODV) OF THE 

 OYSTERS IN FLOATING. 



I. The changes in the constituents of the body were mainly 



* The technical terms here used demand perhaps a word of explanation. The "water-free 

 substance" is the dry matter which is left when the water has all been driven out. Over 

 tliree-quarters of the whole weight of the flesh ("'solids ") of oysters is water, so that the 

 water-free substance makes less than one-fourth of the whole weight. As the oysters are 

 ordinarily sold, i.e. after being floated, the flesh averages about one-fifth water-freb sub- 

 stance. Taking both the flesh ("meat") and liquids ("liquor") together, the oysters as 

 commonly retailed in our markets are about seven-eigliths water and one-eighth water-free 

 substance. That is to say the actual nutritive material in oysters as we usually buy them 

 makes on the average just about one-eighth of the whole weight. It is worth noting that 

 this proportion of actual nutriment is very near the same as in milk. The protein includes 

 the parts of the oyster that are similar to the lean of meats, white of egg, casein of milk, 

 &c The quantities of protein and of fatty and oily substance in the flesh of oysters is 

 smaller, while that of carbohydrates (substances allied to sugar and starch) is far larger 

 that in ordinary meats. 



