New York AGRICULTURAL EXPERIMENT STATION. 109 
The results are given below in comparison with some disges- 
tions in which 0.4 per ct. of acid was used at the start and none 
added afterwards. 
TaBLr XV.—SHOWING INFLUENCE OF INCREASING AMOUNTS OF 
. Acip Upon DIGESTION oF CHEESE. 
Hyprocutoric | PercenTAGE oF NITROGEN IN MATERIAL 
Total ACID USED IN IN ForM oF WATER-SOLUBLE NITROGEN 
nitrogen DIGESTION. 
MATERIAL. in each 
bottle. | added | Added | ina | ing | Ings | Inds | In72 
at start. | meres hours. hours. | hours. | hours. | hours, 
Grams. | Per ct. | Per ct. | Per ct.| Per ct. | Per ct. | Per ct. | Per ct. 
0. 
1. Cottage cheese....) 0.772 CLS arerorete | ZSelds POLS20) | 9249") 90°81 90.44 
2. Cottage cheese....| 0.772 | ...... | 0.9 | 86.54 | 93.91 | 94.56 | 91.96 93.26 
ee Cheddar cheese....| 0.772 QA: | asi hanvare 63.08 | 72.80 | 80.32 | 76.04 | 83.28 
. Cheddar cheese....} 0.772 | ...... 0.9 | 78.10 | 75.91 | 80.97 | 87.95 90.68 
The addition of 0.4 per ct. of hydrochloric acid at the begin- 
ning of the digestion, followed by an addition of 0.1 per ct. 2 
hours after, increased the amount of digested proteid very notice- 
ably at the first examination, 4 hours after the digestion ‘began. 
This was true in both cottage and cheddar cheese. As in pre- 
vious cases, the cottage cheese was more completely digested 
than the cheddar cheese. 
(8) Summary of results of digestion experiments. (a) In the 
absence of acid, paracasein fails to be digested by pepsin, while 
paracasein monolactate (the chief nitrogen compound of fresh 
cheddar cheese) paracasein dilactate, casein monolactate, and 
casein dilactate (cottage, or Dutch, cheése) are partially digested. 
Paracasein monolactate and casein monolactate, in the absence 
of acid, are digested more than are paracasein dilactate and 
casein dilactate. 
(b)In the presence of 0.4 per ct. of hydrochloric acid, para- 
casein dilactate is digested by pepsin more than is paracasein 
monolactate. Paracasein monolactate and dilactate and casein 
monolactate and dilactate and casein dihydrochloride digest more 
readily and extensively in the presence of free hydrochloric acid 
than in its absence. 
(c) Casein dilactate and casein dihydrochloride do not differ 
in the rapidity and extent to which they are converted into solu- | 
ble compounds by pepsin. 
(d) The addition of acid after the beginning of the digestion 
increases the amount of proteid digested, whether we use cottage 
cheese or cheddar cheese. 
