AGRICULTURAL CHEMISTRY — AGROTECHNY. 21 



tributyrin to from 5 to 10 cc. of milk and then shaking slightly, woman's milk 

 gives in a few minutes a marked penetrating odor of butyric acid. This does 

 not occur with cow's milk. 



The reaction is recommended for the differentiation of raw human from raw 

 cow's millv, and also raw from boiled human milk, since tlie action depends upon 

 the presence of a lipolytic ferment in woman's milk. The hemolysin noted in 

 woman's milk is identical with the lipolytic cleavage products (soaps) obtained 

 from the milk fat when the milk is kept in the refrigerator for 24 hours. 



The so-called nitrog'en-free extractive substances in feeds and foodstuffs, 

 J. KoNiG (Ztschr. Untersuch. Nahr. u. Genussmtl, 26 (1913), No. 6, pp. 273- 

 281, fig. 1). — On the basis of investigations reported previously (E. S. R., 18, 

 p. 664; 23, p. 110) the nitrogen-free extractive substances may be grouped into 

 four classes, namely, pentosans, hexosans, ligiiins, and cutins. The first three 

 groups, which occur in feeding stuffs in various condensation or soluble forms, 

 are here described. It is deemed essential when examining tliis class of ma- 

 terial to use the same method the world over in order to obtain comparative 

 results. The methods of analysis are regarded as by no means perfect. 



Som.e effects of feeds upon the properties of lard, I, II, C. L. Hake {Jour. 

 Indus, and Engin. Chem., 2 {1910), No. 6, pp. 264-268; 5 {1913), No. 5, pp. 

 J/10-414, fiffs. 6). — Summarizing the results of the first of these papers, it was 

 found that " corn may be fed without regard to time limit in so far as con- 

 cei'ns any unfavoi-able effect on the properties of the lard. Soy beans and 

 peanuts both produce oiliness in the hogs and the lards resulting are extremely 

 soft. The fat of oily hogs can be hardened by rations of corn, cotton-seed meal, 

 or tankage — the two latter producing unusually firm lards. The possibility 

 is suggested that legumes when fed green may produce soft fats." 



The wide differences in properties which may be conferred upon lards by 

 different feeds are shown by the following figures: A pig selected from the 

 soy-bean fed lot had lard with an iodin value of 100.5, an iodin value of the 

 liquid fatty acids 119, and a saponification value of 197.5, while a pig fed slaugh- 

 ter-pen refuse and weighing about 200 lbs. when slaughtered, showed for the 

 lard an iodin value of 40.35, an iodin value of the liquid fatty acids 78, a 

 saponification value of 203.2, and a melting point of 4S.2. The lard of this 

 second pig presented much the appearance of beef tallow and its constants 

 possessed much the same value as those of beef fat. It also responded readily 

 to the Belfield test for beef fat. 



The second paper reports the results of examining more than 200 samples 

 of lards. It is shown that "fats change in composition with remarkable 

 readiness under the influence of certain feeds, small amounts of these feeds 

 producing striking changes in the properties of the fats." " Corn, and mixed 

 feeds containing corn with wheat shorts, skim milk, or cowpeas, produce fats 

 which possess like properties. Tankage produces a slightly firmer fat, while 

 cotton-seed meal produces fats which contain small amounts of unsaturated 

 acids, and which may remain solid at temperatures of 100° F. or above. Soy 

 beans and peanuts produce lards which contain extreme amounts of unsaturated 

 acids and are fluid at ordinary temperatures." 



" Between the ages of 4 months and 8 months, age of the animal has essen- 

 tially no influence upon the properties of the lard. Using feeds differing as 

 much as 5 per cent in protein content, there is observed no change in the 

 properties of the lards produced therefi'om. With the advent of the various 

 new feeds used in pork production, the iodin absorption number of a lard 

 possesses no value as a means of detecting adulteration." 



