[7] 



DIGESTIBILITY OF FISH IN GASTRIC JUICE. 



1115 



" The haddock is somewhat closely allied, but is inferior in digesti- 

 bility," while "the flounder is light and easy of digestion, but insipid." 

 With all these statements our results agree perfectly, assuming the 

 white-fish of our experiments to be analogous to the English whiting. 



Maly,^ in speaking of the digestive processes in the living stomach, 

 says that raw flesh is more slowly digested than cooked, probably for 

 the reason that with dilute acids the coagulated albumen of cooked flesh 

 is more easily converted into acid albumen. Likewise, that the flesh of 

 young animals is more rapidly digested than that of older ones, while 

 fat flesh is but slowly attacked, as the melted fat surrounds the muscle 

 fibers. With reference to the first of these statements, Jessen ^ found, 

 by experimenting with perfectly lean beef of known age, that he had 

 only a small indigested residue in an artificial digestion of the raw beef, 

 but with the same amount of partially boiled beef a much larger amount 

 remained indigested, and when thoroughly boiled a still larger residue 

 was found. Taking, the amount of indigested residue as a measure of 

 the digestibility, the proportion with the same sample of beef was as 

 follows: Kaw beef, 100; partially boiled, 167; thoroughly boiled, 317. 

 The gastric juice employed by Jessen, however, could hardly be consid- 

 ered as made up of a dilute acid, containing, as it did, 2.5 and 5 per 

 cent of concentrated hydrochloric acid. 



In our own experiments, with a gastric juice containing but 0.2 per 

 cent of pure hydrochloric acid, positive results were obtained as follows : 



First sample of beef. 



Eaw. 



Cooked 

 (steamed). 



Second sample of beef. 



Amount digested from 20 grams . 

 Relative proportion 



4. 0792 

 100.0 



3. 8610 

 94.65 



Kaw. 



4. 3785 

 100.0 



Cooked 

 (steamed). 



4. 1607 

 95.04 



The difference here, then, is not so great, though sufficiently pro- 

 nounced to indicate plainly the influence of cooking. 

 A similar experiment with a sample of bluefish gave a like result : 



Amount digested from 20 grams. 

 Relative proportion 



Raw. 



3. 7617 

 100.0 



Cooked 



(steamed). 



3. 5885 

 95.39 



With the raw beef, however, digestion was so near complete that a 

 second experiment was tried with a larger quantity, as follows: 



From 20 grams. 



From 30 grams. 



Amount digested (raw beef) . 

 Relative proportion 



4. 3785 

 100.0 



5. 7610 

 131. 57 



' Hermann's Handhuch der Pliysiologie, 5, 111. 

 ^ Zeitschrift fiir Biologie, 19, 128. 



