244 REPORT OF THE CHEMIST OF THE 
result of treating pure casein with acid, and C representing the 
result of treating with water casein that had taken up acid, 
It will be noticed that the ratio tabulated in column P, Table XI, 
reaches a minimum in one hour and then gradually increases. This 
increase is probably due to the formation of traces of dissolved 
casein, which, like acid globulin and albumin, as already mentioned, 
is doubtless a relatively weak conductor. The fixation of a very 
small amount of free acid in the form ot soluble acid-casein would 
cause a noticeable decrease in the conductivity of a solution so 
dilute. In the second filtrate of No. 6, the xanthoproteic reaction 
showed traces of dissolved proteid. 
Effect of temperature upon the action of casein in taking up 
hydrochloric acid.—The effect of increase of temperature is shown 
by a comparison of the data contained in Tables XII and XIII 
following, with those in Tables VIII and IX. The time of contact 
in the experiments was not extended beyond 6 hours in most cases, 
because the casein undergoes marked solution when contact is pro- 
longed at higher temperatures (25° and 45° C.) even in the case of 
very dilute acid. The agitation was performed by hand at intervals 
and was as nearly uniform as possible in all cases, except that with 
N-2000 acid at 25° C. the flasks were constantly in motion on the 
shaker. 
TABLE XII.—SHowING AMOUNTS OF HyprocHLorIc AcID TAKEN UP BY 
CASEIN AT 25°C. 


| Concentra- | Concentra- 












Spada Shae ean paces, td Ratio oe 7 
an A eae ave of acid in | conc’n aci egree 
Berea Salers Pea on we tean eat a thatan in casein a 
normality x 2s ee ie solution to solution 
of acid contact. Sere 4) ge eo eae taken up conc’n acid |of casein. 
used. Bolution) tela eackiate by casein. in water. 
N-2000 See Table| IX. 
N-1000 0 .9766 0 0 0-450) 25 OR 
200 cc. 15 min: .7330 48.7 25.0 66.5 0 
for 1 gram 45 min. .6971 55.9 Pein Tf 80.2 0 
of 14 hrs. .6735 60.6 Shoal 90.0 0 
casein ay) jaback .6594 63 .4 32.5 96.0 0 
6 hrs. .6368 67.9 34.8 106.7 1 
N-500 0 1.984 0 0 0 esa ae 
200 cc. 15 min. 1.569 83 .0 20.9 52.9 0 
for 1 gram 45 min. WasRy 130.4 32.8 97.8 0 
of casein 1% hrs. L251 140.6 35.4 109.7 1 
3. hrs 1.262 144.4 36.4 114.4 1 
6 hrs 1.247 147.4 sayfa 118.2 2 
N-125 0 7.907 0 0 00. eee 
100 ce. 5 min. 4.079 382.8 48.4 93.9 1 
for 1 gram 15° min, 3.901 400.6 | "50.6 LOZST 2 
of casein 45 min. 3. OBL | 424.6 | 53.7 116.0 3 
24 hrs. 3.509 439.8 55.6 125.4 4 
iD Suhirsy 3.305 460.2 | yoda 139.3 i 
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