1919] AGRICULTURAL CHEMISTRY — AGROTECHNY. 409 



normal starch and nitrogen-free extract appear to be higher and the fat lower 

 in soft than in mature corn. 



As a basis for grading corn for feeding purposes, the authors recommend the 

 determination of anfid nitrogen together with the degree of acidity. The 

 calorific determination is considered to be of little value. 



Ilex vomitoria as a native source of caffein, F. B. Powee and V. K. Chesnut 

 {Jonr. Avier. Chcin. Soc, U (1919), No. 8, pp. 1307-1312, pi. i).— The authors 

 have applied the method noted on page 412 to a systematic examination of 

 representative samples of /. vomitoria and of other American species of Ilex 

 for the purpose of determining their availability as a commercial source of 

 caffein. 



It was found that an abundant source of caffein is available in /. vomitoria, 

 but that no other North American species of Ilex appears to contain caffein. 

 It is also not found in the leaves of the European holly (/. aquifolium). 



Isolation of the iodin compound which occurs in the thyroid, I, E. C. Ken- 

 dall (Jour. Biol. Chcm., 39 (1919), No. 1, pp. 125-147. fixjs. 2).— The author de- 

 scribes in detail the investigations of the chemical constituents of the thyroid 

 gland leading up to the isolation of thyroxin, the iodin-containing compound to 

 which the activity of the gland is ascribed. A discussion is included of the 

 various conditions which influence the isolation of thyroxin in pure crystalline 

 form. 



Previous reports on this subject have been noted from other sources (E. S. 

 R., 39, p. 803). 



The catalytic decomposition of hydrogen peroxid, G. Phragm^n (Meddel. 

 K. Vctensk. Akacl. Nobelinst., 5 (1919), No. 22, pp. 13, figs. 5). — The decomposi- 

 tion of hydrogen peroxid in alkaline solutions is shown to depend upon some 

 catalyzer present either in the solution or in the glass of the apparatus em- 

 ployed. The extent of decomposition of hydrogen peroxid by living yeast cells 

 was found to depend upon the amount of the yeast and, to a less extent, upon 

 the H-ion concentration. 



Catalase action in yeast cells, H. von Euler and R. Blix (Meddel. K. 

 Vetensk. Akad. Nobelinst., 5 (1919), No. 23, pp. 26, figs. 2').— The catalase action 

 in yeast cells is shown to be increased about 6 times by the addition of a small 

 amount of protoplasma poison such as toluol or chloroform, from 10 to 15 

 times by drying the cells in air in such a way that the enzym is not destroyed, 

 and from 20 to 25 times by heating an emulsion of the fresh yeast for from one 

 to two hours at a temperature of from 55 to 63° C. 



Studies of the concentration of catalase in urine, chyme, and feces, A. V. S. 

 NoRGAARD, (Jowr. Biol. Chem., 38 (1919), No. 3, pp. 501-514, figs. 5).— This paper 

 describes methods of estimating catalase in urine, chyme, and feces, and dis- 

 cusses the interpretation of results from a chemical standpoint. The pyometer, 

 or apparatus for measurement of oxygen, which is used by the author in 

 catalase determinations is described and illustrated. 



Action of enzyms upon starches of different origin, H. C. Sherman, F. 

 Walker, and M. L. Caldwell (Jour. Amer. Chem. Soc, 41 (1919), No. 7, pp. 

 1123-1129). — This paper reports the results of a comparative study of the hy-' 

 drolysis products of various purified starches as brought about by the action 

 of different purified enzyms. The investigation included experiments upon the 

 hydrolysis of wheat, maize, rice, and potato starches by means of saliva, pan- 

 creatin, purified pancreatic amylase, malt extract, purified malt amylase, taka- 

 diastase, and purified amylase of Aspergillus oryzw. The general plan was to 

 purify the starches in four different ways: (1) Washing with water only, (2) 

 with very dilute alkali, (3) with ether after washing with water, and (4) with 



