1916] AGRICULTUEAL CHEMISTRY — AGROTECHNY. 203 



the conditions of pregnancy seemed to have no influence on tlie acetone con- 

 tent of the milk. 



The quantity present in mare's milk varied between 0.48 and 0.97 niR. with 

 an average of 0.71 nig. per liter in five determinations. In ewe's milk for 

 tive determinations the variation was found to be between 0.48 and 0.08 mg., 

 with an average of 0.56 mg. per liter. The amount in goat's milk varied from 

 0.97 to 1.45 mg., with an average of 1.07 mg. per liter for six determinations. 

 Unilateral thyroidectomy had no influence on the acetone content of the 

 milk. In human milk the variations were found to be between 0.48 and 1.16 

 mg. per liter. 



The procedure used by the author for the determination of the acetone was 

 to precipitate the protein of the milk with a 10 per cent solution of tannic 

 acid, then distill the acetone in the usual manner, and titrate with a standard 

 iodin solution, using a finely calibrated burette. 



Studies on the reducing properties of milk, J, SamSula {Wiener Tierdrztl. 

 Monatsschr., 2 (1915), No. 12, pp. 545-552). — The author has repeatedly observed 

 that if two samples of middle milk are drawn from any quarter of the udder 

 of a healthy cow, the one in a sterile container and the other simply in a clean 

 container, both samples will decolorize methylene blue in the same period of 

 time. After being kept at room temperature, however, for about eight hours 

 the sterile sample will decolorize methylene blue much sooner than the other 

 sample. The difference in time of decolorization is considerable and not easily 

 explained. 



It is indicated that the bactericidal property of milk probably plays a role 

 in the phenomenon, and that by its activity it destroys the reducing enzym. 



The analysis of waxes with special reference to beeswax and wool wax, 

 F. W. RicHAEDSON and G. A. Bkacewell {Jour. Soc. Chem. Indtis., 35 (1916), 

 No. 3, pp. 160-163). — The following average values, obtained from the analyses 

 of three samples of beeswax, are submitted : Unsaponifiable matter — Hiibl iodin 

 value, 8.06; butryo-refractometer at 75° C, 21.3; refractive index at 75°, 

 1.4386. Saponifiable matter — melting point, 53.9° ; butyro-refractometer at 50", 

 31.1; refractive index at 50°, 1.446; calculated butyro-refractoraeter at 75°, 

 15.6 ; Hiibl iodin value, 11.9. 



The average composition of wool wax obtained is given as follows: Saponi- 

 fiable matter — free fatty acids, 2 per cent ; neutral esters, 56 per cent. Un- 

 saponifiable matter — 42 per cent. The wax itself has the following values: 

 Hiibl iodin value, 25 ; acid value, 4 ; butyro-refractometer at 50°, 76. Fatty acids 

 in the saponifiable matter: Hiibl iodin value, from 8.5 to 10; melting point, 42° ; 

 butyro-refractometer at 50°, 45; neutralization value, from 136 to 150. The 

 unsaponifiable matter has a refractive index of from 1.489 to 1.495, Hiibl iodin 

 value of from 40 to 50, and acetyl saponification value of 135. 



The analytical procedures used in separating the saponifiable and unsaponi- 

 fiable matter are outlined in detail. Other analytical methods are also de- 

 scribed. 



Researches on the nature of enzym action. — IV, The action of insoluble 

 enzyms, W. M. Bayliss {.Jour. Physiol., 50 (1915), No. 2, pp. S5-94).— Contin- 

 uing work previously noted on the nature of enzym action (E. S. R., 31, p. 608), 

 it has been shown that urease, lipase, emulsin, invertase, lactase, papain, perox- 

 idase, and catalase are active in media from which they can be filtered by ordi- 

 nary filter paper, while the filtrates are inactive. Suspensions of solid prepara- 

 tions of pepsin and trypsin in strong alcohol are decidedly more active than 

 the filtrates of such saturated solution.s. These enzyms seem to be able to 

 assume a colloidal state in such solutions to a small degree and thus to exhibit 

 a slight activity. 



