68 o 
Journal of Agricultural Research 
Vol. V, No. is 
mixture before any determinations were made. The filtrate was used in 
the determinations of amino nitrogen. 
Amino nitrogen. —Van Slyke’s (1912) apparatus and method were 
used in this determination in exactly the same manner for the hydrolytic 
mixtures, digestion mixtures, and control determinations on the reagents, 
leucin and pure casein. In every case the reaction between the reagents 
and the solution introduced into the apparatus was allowed to go on for 
exactly 20 minutes. Two, and sometimes three or four, determinations 
of amino nitrogen were made on every sample mentioned in Table V. 
The distribution of nitrogen was not studied in beef and veal samples 
1 to 7. Two determinations on the same solution of hydrolyzed beef or 
veal generally differed by 2 per cent; thus, the figures obtained for veal 
sample 8 were 70.2 and 72.3 per cent of the total nitrogen present in the 
amino form. The average of these, 71.2 per cent, is the figure recorded 
in Table V. . The extremes in this respect were: Beef sample 11 with 
71.6, 74.6, and 75.8 per cent, a difference of 4.2 per cent between the 
highest and lowest figures, and beef sample 12 with 74.2, 74.4, and 74.7 
per cent, the difference being 0.5 per cent. When the difference of 2 
per cent was obtained with the first duplicates it was believed to be due 
to error in procedure. Accordingly, the determinations of the next 
sample, veal sample 9, were made with the greatest care but with no 
closer results. Numerous modifications of the method were tried without 
the desired result. A large number of results were obtained on veal 
Sample 9 and skim-milk sample 2, all of which were low by several per 
cent and have been omitted from Tables V and XII. The fact that any 
deviation from the procedure used for beef and veal samples 8 gave 
uniformly low results led to its use without modification throughout the 
remainder of the work. 
Table V .—Distribution of nitrogen in beef and veal hydrolyzed by hydrochloric acid 
[Total nitrogen=ioo per cent.] 
Sample No. 
Ammonia 
nitrogen. 
Amino 
nitrogen. 
Nonamino 
nitrogen, 
by dif¬ 
ference. 
Melanin 
nitrogen. 
Experi¬ 
ment No. 
Beef 8. 
Per cent. 
7. 6 
Per cent. 
70.9 
71. 2 
74 - 5 
73 - 1 
74. 0 
70. 8 
74. 4 
73 - 5 
Per cent. 
20. O 
Per cent. 
i* 5 
i* 7 
.8 
j* 26 
Veal 8. 
7. 4 
19. 7 
17. 6 
19. 0 
19. 4 
20. 5 
17. 6 
20. 3 
Beef 10. 
7 * 1 
7 - 1 
6. 8 
I 
Veal 10... 
1. 0 
/ 30 
Beef 11. 
.8 
Veal 11. 
7 - 4 
1. 3 
| 32 
Beef 12. 
7 - 5 
5. 6 
. 5 
\ 
Veal 12. 
.6 
/ 34 
Average: 
Beef 8 to 12. 
7.2 
6.9 
73-4 
72. 1 
18. 6 
. 9 
Veal 8 to 12. 
i 9*9 
1. 1 
Beef 1.1. 
6.8 
75 - 0 
75 * 1 
71.8 
72. 1 
17*4 
17. 1 
16. 1 
.8 
Veal 1.1. 
6. 7 
1. 1 
\ 33 
Casein 1... 
i 
10. 4 
10. 1 
1. 7 
29 
Casein, by Van Slyke. 
16. 1 
1.8 
