1916) FIELD CROPS. 823 



water when neutral or alkaline, and acidity, in addition to retarding enzymatic 

 action presumably including respiration, operates to decrease imbibition by 

 plant tissues. 



Having found that plant cells show the greatest capacity for imbibition of 

 water, not In acidified, but in alljaline solutions, the author has attempted to 

 find substances or mixtures of substances that behave in a lilie manner. The 

 effect of increasing percentages of agar in a gelatin mixture has been inresti- 

 gated, from whicli it appears that the mixture swells more in distilled water 

 and less in acid or alkali. Concerning the relative efOects of acid and alkali, 

 definite conclusions have not been reached, but the data suggest that acid tends 

 to increase imbibition at the ends of the series, while alkali tends to increase it 

 in the mixtures containing the two colloids in more nearly equal proportions. 



The penetration of balanced solutions and the theory of antagonism, W. 

 J. V. OsTEBHouT (Science, n. ser., 44 (1916), No. 1133, pp. 395, 396).— It is stated 

 that antagonism has been explained by assuming that antagonistic substances 

 prevent each other from entering the cell. A difiiculty is said to be found in 

 the fact that they slowly penetrate the cell even in a properly balanced solution. 

 This difficulty, however, disappears if it is supposed that the antagonistic sub- 

 stances affect certain life processes which conti'ol permeability. So long as they 

 are present in the right proportions their effect on these processes is favorable 

 and their penetration into the cell can do no harm. The preservation of normal 

 permeability is regarded as the result rather than the cause of antagonism. 



Antagonism and Weber's law, W. J. V. Osteehout (Science, n. ser., 44 

 (1916), No. 1131, pp. 318-320). — The fact that Weber's law governs antagonism 

 is explained by a dynamical theory formulated by the author. This theory as- 

 sumes that injury and death result from processes which are inhibited by salt 

 compounds formed by the union of salts with protoplasm. If these compounds 

 are formed in a surface, the amounts will, above a certain limit, be independent 

 of variations in concentration and will depend only on the proportions of the 

 antagonistic salts. 



FIELD CROPS. 



Transpiration as a factor in crop production, T. A. Kiesselbaoh (Nebraska 

 Sta. Research Bui. 6 (1916), pp. 3-214, ftffS- 4S)-— Part 1 of this bulletin is de- 

 voted to a discussion of work by earlier investigators in measuring the water 

 loss through plants, the methods employed in the present study, and the factors 

 influencing the results; part 2 to the description of the experiments and the 

 presentation of the data secured ; and part 3 to the application of the results 

 in farm practice. The investigations were conducted to determine principles 

 underlying the use of water by crops, and for this purpose plants were grown 

 to the maturity at which they are usually harvested and under controlled con- 

 ditions in pots, generally 16 by 36 in. in size, having a capacity of approxi- 

 mately 250 lbs. of moisture-free soil and sufficiently large to produce a normal 

 plant. Means taken for the elimination of errors are discussed and 88 refer- 

 ences to the literature cited are given. 



Corn was grown to study the relation of environmental factors to the water 

 requirement. Sunflowers and several sorghums were compared with corn, and 

 a number of varieties differing in acclimatization and plant characters were com- 

 pared with each other. The rain was excluded from the pots and evaporation 

 from the soil surface was reduced to an almost negligible amount. Nearly all 

 pots were situated in a corn field with their top level with the surrounding land, 

 and the plants produced normal yields. 

 69107°— No. 9—17 3 



