Jan. 10, 1916 
Mature Beef and Immature Veal 
693 
rate of digestion when such a difference existed. Accordingly, in experiment 19, 
veal sample 5 was compared with a sample of raw skim milk obtained in the fresh 
condition from the Dairy Division, Bureau of Animal Industry. Instead of 100 gm. 
of beef, 600 gm. of the skim milk were transferred to a 2-liter Erlenmeyer flask. The 
specific gravity of skim-milk sample 1 was 1.0352 at 26° 0., and, hence, the volume 
of the 600 gm. was 600/1.0352, or 579.2 c. c. This was regarded as if it were 100 gm. 
of beef plus 479 c. c. of water. To this amount, 316 c. c. of water were added, the 
milk being kept in a boiling-water bath for five minutes. It was kept in cold storage 
overnight with veal sample 5; the next morning it was treated in the usual way 
along with this sample. At the beginning of the digestion the volume of the skim- 
milk digestion mixture was 2,096 c. c., which is practically the volume of the meat 
mixtures—i. e., 2,000 c. c. plus the volume of 100 gm. of meat, which lies between 
75 and 100 c. c. A similar sample of skim milk in 0.2 per cent hydrochloric acid 
was used for the determination of extractive nitrogen. Skim-milk sample 1 con- 
Fig. i —Experiment 14. Curve showing the quantity (in cubic centimeters) of Nf5 nitrogen in 100 c. c. 
of digestion fluid, equivalent to approximately 5 gm. of meat; used 100 gm. of meat, 2,000 c. c. of 0.2 per 
cent hydrochloric acid, and 200 mgm. of pepsin 1. 
tained 2.05 c.c.of AT/y nitrogen per gram, or 0.574 per cent. The extractive nitrogen 
was 6.3 per cent of the total nitrogen. 
In precipitating the undigested proteins and the acid proteinate by neutralization 
and heat, care was taken to test the filtrates with acid and alkali, in order to be certain 
that precipitable protein was not present in any of the filtrates. The complete 
precipitation, though troublesome, was not difficult. The precipitates, containing 
both undigested proteins and acid proteinate, were determined for nitrogen by the 
Kjeldahl method in the usual manner and the results recorded under the heading 
“Quantity (in cubic centimeters) of AT/y acid proteinate nitrogen.” The figures for 
proteose and peptone nitrogen obtained from the filtrates indicate that this trans¬ 
formation was more rapid in the skim milk than in the veal. This is, of course, easily 
accounted for by the fact that the skim-milk proteins were in solution or suspension 
at the beginning of the digestion, while the veal particles took time to go into solution. 
Digestion in trypsin sodium carbonate solution. —In general, these experiments 
were carried out in exactly the same way as the digestions in pepsin hydrochloric 
acid solution. Dry, powdered trypsin preparations were used. ,Portions of these 
were weighed and transferred to the digestion mixtures in the same way as the pepsin. 
Instead of 1 liter of 0.4 per cent hydrochloric acid, the same volume of 1 per cent 
sodium carbonate was added. The digestions in experiments 15 to 34 (Tables X and XI) 
