AGRICULTURAL BOTANY. 25 



Various conclusions are drawn from earlier exi)erinients, which are modified 

 somewhat, and the authors state that the germination of the seed of castor bean 

 is associated with a remarkable activity of the cells of the endosperm, which set 

 up a very complex metabolism. The protoplasm takes a prominent part in the 

 metabolic changes produced, secreting enzyms. and causing various chemical 

 changes in the cells. In this renewed activity the embryo contriI)utes to enzym 

 formation, and the result is the production of a great variety of nutritive 

 material, part of which is the direct product of enzym action and i)art is due to 

 the secretory activity of the protoplasm as well as to the interaction of the 

 products of both these agents. Two varieties of sugar, lecithin, fatty acids 

 and the products of their oxidation, proteids and the products of their digestion, 

 including various nitrogenous bodies, amino-compounds, and amido-compounds 

 are present. Analyses of the cotyledons showed them to contain varying quan- 

 tities of lecithin, in some cases amounting to L.30 per cent of their dry weight. 

 Both sugars may be detected in the cotyledons, the relative amounts varying, 

 I'ut cane sugar being usually i)resent in the largest quantity. 



The reaction of the cell sap is acid, showing traces of jihosphoric acid mixed 

 with an organic acid whose nature has not yet been ascertained. It is probable 

 tiiat in the transportation of the nutritive substances to the embryo the proto- 

 plasmic threads in the cell walls play an important part, and dialysis undoubt- 

 edly i)lays a large part in the absorptive processes, especially where crystalline 

 substances are concerned. 



On stimulants of nutrition in plants, II. Micheels (Kcv. Sci. \P(iri.^]. .7. 

 ser., 5 (1906), No. 14, PP- -)27W/2.9). — Experiments on the influence of solutions 

 of colloidal tin on the germination and early grow^th of wheat, oats, peas, buck- 

 wheat, etc., are reported, showing that this substance has a very marked influ- 

 (iice in promoting germination and growth. It apparently acts upon the reserve 

 material of the seed in nuich the same manner as diastase or other ferments. 



On the nature of the galvanotropic irritability of roots, A. J. Ewakt and 

 Jessie S. Bayijss [I'roc Uoij. Soc. [L(jii(l(jii\. Sci: li. 77 {1905), No. B 51-'i, pp. 

 6S-66). — The authors review and attempt to explain the contradictory state- 

 ments of a number of investigators on the nature of the galvanotropic irrita- 

 bility of roots, after which they briefly describe some experiments which tend 

 to show that the galvanotropism of roots is due to chemotropic stimulation by 

 the products of electrolysis, of which the acid is more effective than the alkali. 

 It is claimed that in Brunchhorst's experiments, which seem to show that sti'ong 

 currents produced a curvatui'e toward the positive electrode and weak ones 

 toward the negative electrode, the electrolysis probably occurred in the super- 

 ficial cells of the roots submerged in water, the tissues being sufficiently imper- 

 meable to the liberated acid and alkaline ions to allow them to accumulate 

 beyond the minimum for stimulation. Although the curvature is usually sharp 

 and strongly localized to the point of application of the electrode, the indica- 

 tions are that the response is a stimulatory one and is not due to the direct 

 action of the products of electrolysis, retarding growth on one side or acceler- 

 ating it on the other. 



The action of certain organic substances on the form and structure of 

 leaves, M. Molliard (Bui. tioc. But. France, 33 (1906), No. 1, i>p. 61-6.5). — 

 Experiments are reported that were conducted to determine the relation which 

 exists between the structure of some of the higher plants and the organic medium 

 in which they were grown. All the experiments were with radishes, one lot 

 being grown in mineral solutions, the others in various forms of carl)(>hydrates. 

 The growth in the mineral solutions was comparable with that of ijlants grown 

 under normal conditions, but when grown in solutions of saccharose, glucose, 

 levulose, dextrin, etc., the morphological structures showed marked departures 



