75 



two samples of veal, and also of two bluefish (88.69 and 73-44)- As direct 

 evidence that age, sex, etc., do exert a modifying influence on the digestibility 

 of flesh, we have three experiments on the flesh of the lobster ; one with a 

 small young lobster, a second with a large female, and a third with a large 

 male of the same species. The duplicate digestions gave fairly concordant 

 results ; the average relative digestibility being for the young specimen 87.81, 

 for the large female 79.06, and for the male 69.13. This shows plainly some 

 modifying influence in the flesh itself. In composition, so far as the solid 

 matter is concerned, there was no appreciable difference in the three samples. 

 Bearing in mind, however, these possible variations, it is very evident from 

 our results that the average digestibility of fish-flesh is far below that of beef 

 similarly cooked. In but two instances, in the case of shad and whitefish, 

 does the digestibility of fish-flesh approach that of beef, although, from the 

 average of our experiments, several are as easily digestible as mutton, lamb, 

 and chicken. 



" Pavy states that fish with white flesh, such as the whiting, etc., are less 

 stimulating and lighter to the stomach, or more easy of digestion, than fish 

 with more or less red flesh, as the salmon. Our experiments confirm this 

 statement so far as digestibility is concerned. Thus the average digestibility 

 of the salmon and trout is considerably below the average of the more digesti- 

 ble white fish. The difference between the digestibility of the light and the 

 dark meat of the same flesh is somewhat striking, as in the case of the shad, 

 where the digestibility of the former was found to be 97-25, as compared with 

 beef, while the dark flesh was 87.32. A similar difference, though very much 

 smaller, is to be noticed between the light and dark meat of the chicken. 



"This difference in digestibility is in part due, without doubt, to the 

 amount of fat present, for, as Pavy states, in the flesh of white fish there is 

 but little fat, it being accumulated mainly in the liver of the animal, while in 

 red fish there is more or less fatty matter incorporated with the muscular 

 fibres. For a similar reason, eels, mackerel and herring are, according to 

 Pa\7, less suited to a delicate stomach than some of the white fish, and our 

 experiments show that in digestibility two of them stand below the more diges- 

 tible white fish; mackerel, however, from our single experiment with the 

 white portion of the flesh, showed a comparatively high digestibility. In all of 

 our experiments, however, with white fish, we rejected the outer layer of dark 

 flesh, except in the case of the shad. The varying differences in digestibility 

 are not to be considered as due wholly to differences in the amount of fat in 

 the flesh ; thus the flesh of fresh cod contains but little fat, and yet it is one 

 of the most indigestible of the white fish experimented with. This agrees with 

 Pa\7's experience ' that it is a more trying article of food to the stomach than 

 is generally credited.' Again Pavy makes the following statement, based on 

 his experience in fish dietetics ' of all fish, the whiting may be regarded as the 

 most delicate, tender, and easy of digestion.' ' The haddock is somewhat 

 closely allied, but it is inferior in digestibility,' while 'the flounder is light and 

 easy of digestion, but insipid. ' With all these statements our results agree 



