130 EXPEEIMENT STATION^ EECORD. 



occurring in nature, they think, would probably constitute the first step in the 

 origin of life. 



Hemicellulose in roots, rhizomes, and tubers, A. Stiegee {Hoppe-Seyler's 

 Ztschr. Physiol. Chem., 86 {191S), No. 4, pp. 270-282).— The author details the 

 results of examinations made on the subterranean parts of 15 plants. He found 

 hemicelluloses in all, but was not able to settle the question as to whether 

 these serve as structural or exclusively as reserve material. A bibliography Is 

 given. 



Protoplasmic contractions resembling plasmolysis which are caused by 

 pure distilled water, W. J. V. Osterhout (Bot. Gaz., 55 {1913), No. 6, pp. 

 446-451, figs. 6). — This amplifies a preliminary account already noted (E. S. R., 

 29, p. 134) and gives some details of the study. 



It is stated that in many cases contractions in young cells closely simulating 

 true plasmolysis may take place with great rapidity on immersion in pure 

 water, while older cells respond more slowly and show by alterations of their 

 chromatophores that they are undergoing false plasmolysis. True and false 

 plasmolysis may be produced simultaneously, these contractions usually becom- 

 ing irreversible at a certain point. The effects observed for distilled water 

 were also produced by that from ponds, rivers, and springs, and are therefore 

 held not to be due to toxic products of distillation. 



It is held that the cause of these phenomena is increased permeability of 

 the plasma and internal cell membranes, as the result of which some or all of 

 the osmotically active substances diffuse out. The protoplasm then shrinks as 

 the result of the water loss from the vacuoles, this being often followed by ap- 

 parent coagulation of the protoplasm, with most of the features characteristic of 

 cytolysis in animal cells usually absent. Absorption of water as a cause is 

 precluded by the fact that the cells do not increase in size. The increased per- 

 meability is held to be due to the loss of certain substances upon which the 

 maintenance of normal permeability depends (the most important being the 

 inorganic salts), which is followed by increased permeability of the cell mem- 

 branes as measured by electrical means. 



Toxic inorganic salts and acids as affecting plant growth, C. B. Lipman 

 and F. H. Wilson (Bot. Gaz., 55 {1913), No. 6, pp. ^OM^^)-— Tabulated results 

 are given of preliminary studies made on vetch and wheat as to the effects 

 thereon of varying proportions in the soil of sulphuric acid and of its copper, 

 zinc, and manganese salts, leading to the conclusion that the tolerance of plants 

 for certain of the inorganic salts commonly regarded as A'ery poisonous is much 

 greater than we have been accustomed to believe. Some plants are said to be 

 actually stimulated by quite considerable proportions of such salts. A further 

 search for the limits of toxicity is in progress. The work is claimed to present 

 new evidence regarding the stimulating effects of manganese sulphate on the 

 growth of plants. Certain facts are thought to indicate that the soil flora is 

 permanently modified by the treatment of the soil as herein outlined. 



Arsenic compounds in agriculture and possible danger from their use, G. 

 Ampola and G. Tommasi (Ann. R. Staz. Cliim. Agr. Sper. Roma, 2. ser.^ 5 

 (1911), pp. 263-277, pis. 2; als. in Centhl. Bakt. [etc.l, 2. Aht., 38 (1913), No. 

 7-12, pp. 230, 231). — It was found that arsenic acid is injurious to green plants 

 when present in nutritive solutions in concentrations not less than 1 mg. per 

 liter of water. Bean plants died after 24 days in 3 mg. and maize after 27 days 

 in 5 mg. per liter, lupines showing an intermediate degree of resistance, and no 

 plants showing growth at a concentration of 20 mg. per liter. 



In soil cultures the limits were more difficult to determine on account of 

 absorption, but growth was usually checked at a concentration corresponding 

 to 0.3 mg. of arsenic per kilogram of soil. The arsenic mostly went to the 



