1917] AGRICULTURAL BOTANY. 223 



tailed. The fact that assimilation supposedly requires the presence of both 

 chlorophyll and an enzym is considered to indicate that these factors work 

 together in that process. Chlorophyll supposedly forms a dissociable compound 

 with carbon dioxid. The absorption capacity of green, dry, and powdered 

 leaves for carbon dioxid was studied under different conditions and the results 

 are described. It is considered possible that carbamino compounds may be 

 formed from amino or albuminous compounds. The absorbing substance is sup- 

 posed to act as an accumulator effecting, or favoring, condensation of carbon 

 dioxid. 



Assimilation of organic nitrogen by Zea miays and the influence of Bacillus 

 subtilis on such assimilation, R. O. Brigham (Soil Sci., 3 (1917), No. 2, pp. 

 155-195, pis. 2, figs. 2). — This work was carried out in order to ascertain 

 whether higher plants can utilize organic nitrogen directly without the agj'ncy 

 of micro-organisms, to determine the relative importance of the compounds 

 used, and to show how the utilization of organic compounds by plants is af- 

 fected by the action of a bacterium known to be able to decompose such com- 

 pounds with the production of ammonia. The work includes experiments on 

 the influence of different nitrogenous compounds, in sterile or inoculated 

 cultures, upon the growth of seedlings of two varieties of Indian corn. 



It is stated that Z. mays uses asparagin, casein, cottonseed meal, hemo- 

 globin, linseed meal, uric acid, peptone, guanin, alanin, urea, creatin, malt, and 

 glycocoll, these organic nitrogenous substances being named in order of their 

 availability. Guanidin carbonate, guanidin nitrate, dipheuylamin, caffein, and 

 benzamid are unfavorable to the growth of Z. mays. Guanin is toxic to pop- 

 corn but not to dent corn. 



Organic substances found to be directly available, but to produce better 

 growth when acted upon by B. subtilis were peptone, guanin, alanin, linseed 

 meal, cottonseed meal, casein, hemoglobin, and urea, the last showing this 

 effect only with popcorn. The action of B. subtilis did not increase the avail- 

 ability of urea (by dent corn), sodium nitrate, asparagin, ammonium sulphate, 

 uric acid, malt, creatin, glycocoll, and those compounds which were toxic. 



Substances found to be better than sodium nitrate in case of dent corn were 

 cottonseed meal, linseed meal, casein, hemoglobin, uric acid, and asparagin. 

 Urea, peptone, guanin, alanin, and creatin, though available, were not better 

 than sodium nitrate. Guanin was toxic to popcorn but available to dent corn. 

 The compounds of the benzene ring were found to be exceedingly toxic to the 

 plants tested. 



Ammonium sulphate is said to be a far better source of nitrogen for dent 

 corn than is sodium nitrate, being surpassed only by casein and asparagin. 

 Generally speaking, organic compounds of high complexity are better after 

 ammonification, those of low complexity not being impi-oved thereby. It is 

 thought that nitrification following ammonification would be detrimental. The 

 simpler method of measuring growth by length of leaves gave results very 

 nearly parallel to those obtained by determining the dry weight. 



The catalytic action of potassium nitrate in the alcoholic fermentation 

 produced by Sterigmatocystis nigra, M. Molliaed (Compt. Rend. Acad. Sci. 

 [Paris], 163 {1916), No. 20, pp. 570-572) .—Alcoholic fermentation ascribed to 

 iS. nigra in a nutritive solution, following a 0.2 per cent addition of potassium 

 nitrate, was 3.3 times as active as that produced by the addition of the same 

 quantity of ammonium chlorid. The optimum for the former solution was 

 reached at a concentration of 0.4 per cent, as contrasted with a concentration 

 of approximately 5 per cent required for the optimum fermentation with yeast 

 which has been reported by some other investigators. 

 4066°— No. 3—17 3 



