Per cent ionization = 100 ( ^ KV~ 
APPLE BY-PRODUCTS AS STOCK FOODS. 
sufficient quantity of soluble basic salts or other reactive substances 
must be present to exert a strong buffer action. 24 It is even probable 
that the pectin substances could exert a buffer effect of this magni- 
tude. At any rate, the effect in solution is that of free malic , 
buffered by some malate. For the normality involved the specific 
acidity of a malic-acid solution is approximately ten times that of a 
solution of the acid malate. The pH values in the last two coin 
of Table 8 for acid potassium malate and malic acid were computed 
by the help of the following formula, derived from Ostwald's Dilu- 
tion Law, as explained in detail by Thomas (16) : 25 
KV\ 
2 * . 
r=volume in liters, in which 1 gram-molecular weight 26 of the 
substance is dissolved. 
K=the dissociation constant (the values given for Ka in Scudders 
(15) tables). 
The pH values as thus computed are based on conductivity data 
and not on measurements by the hydrogen electrode. Therefore they 
should not be accepted as absolute. 
Investigation of the amygdalin, or more precisely the hydrocyanic 
acid, content of dried pomace was undertaken because of the well- 
known fact that ripe apple seeds contain important quantities of this 
toxic substance. Huber (88) has reported the presence of from 0.G2 
to 1.38 per cent of amygdalin, corresponding to from 0.037 to 0.082 per 
cent of hydrocyanic acid, in the dry substance of apple seeds. Auld 
(8) found that as little as 3.9 grains of hydrocyanic acid was fatal 
to an 80-pound sheep when taken in the form of potassium cyanide. 
Corresponding to Huber's highest figure in hydrocyanic acid con- 
tent. 5.74 grains of hydrocyanic acid would be contained in 1 pound 
of seeds. 
Examination of the dried pomace, however, indicated an entire 
absence of emulsin, the enzyme occurring in apple seeds (88), which 
serves to generate free hydrocyanic acid from the glucoside amyg- 
dalin. 
Sample 37199 gave a negative test for hydrocyanic acid, even 
when the enzyme was added to the macerated material. The quan- 
tity of seeds present may have been so small that any acid formed 
on maceration was not sufficient to give the test, or the method of 
preparing the pomace may have been such that the cyanophoric 
compound was changed and did not yield hydrocyanic acid. 
In the examination of sample 37254, the material used in the 
feeding trial, the seeds were separated by hand from the remainder 
of the pomace and tested separately. The seeds constituted 5 per 
cent by weight of the sample, and. with added emulsin, yielded I 
per cent of hydrocyanic acid, corresponding to 0.38 per cen 
amygdalin. This is equivalent to 0.001 per cent of hydrocyanic acid 
in the dried pomace. The pomace material from which the seeds 
had been removed gave a negative test for hydrocyanic acid. 
24 Ruff or action in this case means the power to depress ,i u . formation of hydr 
•By an evideni typographical error in Thomas' article this formula was incorr 
stated: "Per cent ionization=100 V^-" *' — o~*" 
-'■' One gram-molecule. 
44664°— 23 3 
