128 
IOWA ACADEMY OP SCIENCE 
,The limit of accuracy is indicated by the discrepancies between the 
total amounts of nitrogen which should, of course, have been the same, in- 
asmuch as the samples of gluten were prepared at the same time. These 
differences Avere undoubtedly due to variation of AA^ater in the different 
portions. They are not great and not all in the same direction. There 
is no indication, then that the gluten digests at a different rate if 
bleached or unbleached. 
B. Of Bread. The bread made under domestic conditions, AAms raised 
AAoth yeast and baked in a kitchen range, dried, finely puh^erized, to 
produce as far as possible the same surface of the particles, and digested 
AAuth pepsin-hydrochloric acid under the same conditions as the moist 
gluten. The degree of digestibility aa^s determined by the proportion 
of nitrogen AAdiich AA^ent into solution. Table III sIioaaas results. 
TABLE III 
PEPSIN DIGESTION OF BREAD. 
rj-:u CE.XT OF original nitrogen digested. 
Test 
Bleached 
Unbleached 
I 
60.8 
57.2 
II 
69.5 
69.8 
III 
82.9 
86.6 
AVhile there is not absolute agreement nothing indicates that the 
lirotein of the bleached flour is less digestible than that from the un- 
bleached. 
PANCREATIC DIGESTION. 
A. Starch Digstion. This Avas carried on as AAuth the salwary ferment, 
Alerck’s pancreatin being substituted for the saliAuiry ferment. 
B. Gluten Digestion. The gluten Avas extracted from flour as before 
described and thoroughly dried at 100 degrees, then finely ground AAuth 
a coffee grinder. Digestion AA^as carried on at 38 degrees, the soluble 
nitrogen being used to indicate the amount digested. Table TV shoAvs 
results. 
TABLE IV. 
PANCREATIC DIGESTION OP STARCH. 
time of reaching achromic stage. 
Flour Contains 2.68 Parts Nitrite N per Million. 
Test. 
Bleached, 
Unbleached. 
I 
4 min. 
3^2 niin. 
II 
35V> min. 
37 min. 
III V 
35 min. 
33 min. 
