XXXVIII.-ON THE RELATIVE DIGESTIBILITY OF FISH FLESH 



m GASTRIC JUICE. 



By R. H. Chittenden and George W. Cummins. 



[Keprinted from American Chemical JonrDal, Vol. VI, Xo. 5.] 



The value of food as nutriment depends i)rimarily upon the presence 

 in suitable quantitj* of elements, or combinations of elements, capable of 

 supplying the needs of the body; coupled with this, however, is the ease 

 with which the food stuff in question can be rendered available by the 

 system for its wants. This, or in other words its digestibility, constitutes 

 a very important item in determining the true nutritive value of any 

 food. If, of two foods possessing a like chemical composition, one is 

 more easily digestible, that one, though containiug no more available 

 nutriment than the other, is in virtue of its easier digestibility more 

 valuable as a food stuff, aod in one sense more nutritious as well as 

 more economical for the system. 



Both chemists and physiologists have appreciated the importance of 

 all data relative to the nutritive value of foods. But hitherto nearly 

 all work in this direction has been confined to a study of chemical 

 coimposition, and only occasionally to digestibility. The mere fact, 

 however, that a substance contains a certain percentage of nitrogen is 

 not alone sufidcient. We need to know in addition, not only how much 

 of the nitrogen passes through the body unabsorbed, thus indicating 

 how much is ordinarily available ibr nutriment, but we need to know 

 likewise how long the food stuff remains in the stomach, how quickly 

 it is acted upon by the digestive juices, and, finally, how much i)asses 

 out undigested — points of great importance to the healthy system, but 

 still raorti so to the system weakened by disease. 



There are two ways of determining the digestibility of a food stuff in 

 gastric juice. One consists in the introduction of a weighed amount 

 of the subtance into the stomach of a man or animal through a fistulous 

 opening, and noting the length of time required for its solution ; the 

 other, in the use of an artificial gastric juice by which the amount 

 of substance cajjable of being dissolved and digested in a given time can 

 be quantitatively ascertained. The first of these methods was made 

 use of by Dr. Beaumont in his celebrated experiments on the Canadian, 

 Alexis St. Martin, about 1830, and has been employed many times 



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