1010] AGRICULTURAL. BOTANY. 221 



Investigations on the imbibition of water by gelatin, E. B. Shreve {Car- 

 iiGcjie Inst. Wa.'^hington Year Book, 17 (1918), pp. 74-7G). — This is a continua- 

 tion of work previously noted (E. S. R., 40, p. 27). It is said to have shown 

 that it is not safe to draw conclusions regarding the effect which substances 

 within a jelly exert uix)n its iiubibitional capacity when evidence for such a con- 

 clusion lies in the known effect of an external solution of the same substance on 

 that jelly. This applies to the theories involving the physicochemical effect of 

 the substance upon the gelatin itself, as well as those concerning physiological 

 phenomena. 



The effect of organic acids and their aniido compounds on the hydration 

 of agar and on a biocolloid, D. T. MacDougal and H. A. Spoehk {I'roc. ISoc. 

 Expt. Biol, and Med., 16 (11)18), No. 3, pp. 33-35).. — A series of test measure- 

 ments was carried out in the equable temperature chambei'S of the Coastal 

 Laboratory from August to November, 1918, on three groups of substances, (1) 

 succinic acid and its amido compound, a amino succinic or aspartic acid, which 

 are dibasic, and its amid, asparagin, which is monobasic; (2) acetic acid and 

 amino acetic acid or glycocoll, which are mouabasic; and (3) propionic acid and 

 a amino propionic acid or alanin, also monobasic ; data were obtained which are 

 hero partly tabulated with brief discussion. 



It is slated that equimolecular concentrations of the three organic acids pre- 

 sent a small divergence of effect on agar and a more positive dillerence in agar 

 protein. Agar swells more in succinic acid than in its amido compound, but this 

 relation is reversed iu the acetic-glycocoll couple and in the propionic-alanin 

 pair. Equimolecular concentrations of amino acids produce notably greater 

 swellings of the biocolloids in comparison with related organic acids, implying 

 the positive action of factors other than the H-ion concentration. Glycocoll 

 facilitates hydration in all concentrations above 0.01 M. iu both agar and agar 

 proteins, and also in agar gelatin. Asparagin induces a maximum hydration. 



The absorption of calcium salts by squash seedlings, R. H. True and R. B. 

 Harvey {Brooklyn Bot. Gard. Mem., 1 (1918), pp. 502-512, figs. 3). — During 

 work participated in by True (E. S. R., 36, p. 128), it was found that the rate 

 of absorption of electrolytes by seedlings from solutions of the usual mineral 

 nutrients was influenced largely by the chemical character of the substances 

 offered. It appears that the usual salts of potassium were not absorbed, pro- 

 ducing rather an outgoing current of ions fi'om the seedlings into the solution. 

 In case of more dilute magnesium solutions a slight absorption took place, while 

 iu calcium solutions absorption was more considerable and occurred in the most 

 dilute solutions. 



In preliminary experiments by the present authors some exceptional behavior 

 was observed. Results of a series of experiments as here recorded are consid- 

 ered to show that for both squash and white lupine in the seedling stage the 

 calcium ion favors the absorption of ions. The differences iu behavior of the 

 two plants are detailed. The strong influence exerted by the spcciflc character- 

 isterics of the different species of plants is shown by the contrasting behavior of 

 the lupine and the squash in the presence of calcium accompanied by the NO3 

 ion. It is considered as clear from the evidence shown that any theory of cell per- 

 meability framed to account for the income and outgo of the living plant with 

 respect to electrolytes must take into account the striking differences that exist 

 in the behavior of plants toward even such fundamental factors as the re- 

 quired mineral nutrient ions. 



The nucleus as a center of oxidation, W. J. V. Ostebhout (Brooklyn Bot. 

 Gard. Mem., 1 (1918). pp. 342-347). — A study is detailed as made by the author 

 on leaf cells of Indian pipe (Monotropa uniflora), which after being injured 

 132688°— 19 3 



