184 
Philippine Journal of Science 
1920 
All of the total nitrogen determinations were made by the 
Kjeldahl-Gunning- Arnold method (22) using 1 gram of copper sul- 
phate instead of mercury, and boiling for four hours (2) after the 
solution turned clear. The Claisen flasks of 1-liter capacity were 
found to be inadequate and 2-liter distilling flasks, modified for the 
purpose, were used instead. In the estimation of arginine Folin’s 
improved absorption tubes (H) dipping into the standard acid 
were used instead of Folin bulbs, and 20 per cent sodium hydrox- 
ide (20) instead of 50 per cent. The absorption tubqs were kindly 
loaned by the department of physiology of the College of Medicine 
and Surgery. The amino-nitrogen determinations were made at 
no fixed temperature, since the laboratory of agricultural chem- 
istry of the College of Agriculture has no means for controlling 
this factor. Alizarine sodium monosulphonate was used as in- 
dicator in all of the titrations, and it was found more satisfactory 
than methyl orange. The results are recorded in Table 2, and 
are compared with the analyses of some known proteins in 
Table 3. 
Table 3 . — Comparison of nitrogen distribution in the hot-water-insoluble 
portion of copra meal with that in some other products. 
Nitrogen. 
Lactal- 
bumin » 
plus 
equal 
weight of 
dex- 
trose. •> 
Copra 
meal. 
Cotton- 
seed 
meal.c 
Coconut 
globulin.d 
Coconut 
globulin.o 
Per cent. 
Per cent. 
Per cent. 
Per cent. 
Percent. 
Amide 
8. 37 
26.72 
10. 45 
7. 36 
7. 99 
Humin 
3. 70 
7. 11 
7. 78 
0.76 
fl.41 
Cystine 
1.05 
0. 65 
0.96 
Arginine 
8. 10 
11.73 
19. 52 
32. 79 
29.50 
Histidine 
3,22 
3.94 
5.47 
12. 54 
2. 19 
4. 78 
6.41 
58. 79 
41.96 
2.08 
42.82 
6.43 
59.09 
45.44 
4.60 
Non-amino 
Total 
99.35 
101.31 
96. 90 
100.00 
» Gortner, R. A., Journ. Biol. Chem. 26 (1916) 182. 
’’ The presence of tryptophane was tested in the water-soluble protein by the Hopkins-Cole 
and Benedict modified Hopkins-Cole reactions. (12) 
' Grindley, H. S., Joseph, W. E., and Slater, W. E., Journ. Am. Chem. Soc. 37 (1915) 1779. 
Hawk, P. B., Practical Physiological Chemistry. Philadelphia. P. Blakiston's Son & Co. 
(1914) 400. 
' See footnote 3. 
' Humin absorbed by lime. 0.11 humin nitrogen In amyl alcohol extract. 
Table 2 shows that the distribution of nitrogen in copra meal 
is fairly even. As stated above, the hot-water-soluble substances 
were eliminated before the copra meal was hydrolyzed with 
