1026 EXPERIMENT STATION EECORD. 



at wbicli plants could live in pure salt solutions, or the experiments liave been 

 carried on for so short a period as to be considered inconclusive. 



In her investigations wheat of the variety Early Genesee was selected, and 

 for comparison radish and clover seeds were used and found to give results 

 similar to t-hose described for wheat. In all the experiments the seeds were 

 supiKU-ted on filler paper, so that they might germinate in the solution from 

 the beginning, and equimolecular solutions were used of calcium, potassium, 

 sodium, and magnesium, as these salts are the ones commonly found in the soil. 

 Control experiments with tap and distilled water were carried on with each 

 series, and the plants made a better growth in distilled water than in any of 

 the salt solutions, showing that they were all toxic rather than stimulating in 

 the concentrations used. 



The order of germination is recorded, in which it is shown that seeds in 

 potassium chlorid and sodium chlorid were the first to send out roots and for 

 several days remained in advance of those in calcium chlorid and magnesium 

 chlorid, but that after 15 days those in magnesium chlorid were dead, while 

 those in calcium chlorid were still living. In all the solutions the limit of 

 growth was reached in about 30 days. 



The results of the investigations show that the principal soil bases are toxic. 

 The following is the order of toxicity of their chlorids, beginning with the 

 most poisonous: Magnesium chlorid, sodium chlorid, potassium chlorid, and 

 calcium chlorid. Further, experiments lasting but a short time, such as have 

 been reported by most investigators, can not be considered as conclusive as 

 longer experiments. After 6 days plants in sodium chlorid and potassium 

 chlorid made more growth than in calcium chlorid, while after 25 or 30 days 

 the plants in calcium chlorid were considerably in advance of all the others. 



The action of manganese on plants, (i. Salomone (Stas. Sper. A (jr. Itah, 

 JfO (1907), No. 2, pp. 97-117). — A study was made under field conditions to de- 

 termine the influence of a number of compounds of manganese on the growth 

 and dexelopment of maize, oats, onions, and meadow grass. 



In a second series of experiments with one dozen species of economic plants 

 and several cryptogams, the author sought to determine the form in which 

 manganese is found in plants. The manganese salts were found to stimulate 

 the formation of the nitrogenous contents of the plants, the sulphate, nitrate, 

 and binoxid of manganese giving the greatest increase. Manganese was found 

 in many instances in the plant stored as a waste product, while in others it was 

 in such intimate organic combination as not to be readily recognized by the 

 ordinary reagents employed. 



The malignant effect of certain trees upon surrounding' plants, H. S. Reed 

 (Plant World, 10 (1907), No. 12, pp. 279-282, fig. J).— The author describes the 

 growth of coleus under a Kentucky coffee tree in the grounds of this Depart- 

 ment, in which the plants close to the tree were less vigorous than those at 

 some distance. It is held that the conditions of plant growth, such as water, 

 plant nutrients, and light, were not such as could fully account for the harm- 

 ful effects noted upon the surrounding vegetation. The most deleterious effects 

 seemed to be due to organic substances washed from the bark of the tree by 

 rain and left in the soil. Deleterious substances may also be excreted from the 

 roots of trees and, in certain cases, exert an injurious effect on surrounding 

 plants. 



The antitoxic value of complete and incomplete nutrient solutions, A. Le 

 Renard (Essai sur la Valetir Antitoxique de VAlimcnt Complet et Incomplct. 

 Thesis, Vniv. Paris, 1907, pp. 213, dgm. 1). — The author has studies! the action 

 of a large number of chemical substances in overcoming the toxic effect of the 



