522 EXPERIMENT STATION EECOED. 



and even between metals and alkaloid bases. It appears to be greatest between 

 ions of different valency, but to be not altogether absent between those of the 

 same valency. 



The explanation of antagonism considered as most plausible is that which re- 

 gards the plasma membrane as a carrier of ions into the interior of the cell by 

 means of reversible combinations with them, the different ions thus interfering 

 with each other's activity in this respect. 



A bibliography is given. 



Determination of elements necessary to development of maize, P. MAzf: 

 {Compt. Rend. Acad. Sci. IParis], 160 {1915), No. 6, pp. 211-214).— In continu- 

 ance of previous studies (E. S. R., 31, p. 221) the author carried out experiments 

 testing the growth of maize in a nutritive solution of given composition, to 

 which some or all of the elements aluminum, boron, fluorin. iodin, and arsenic 

 had been added. The results appear to show that all of the elements named are 

 necessary to the best growth of maize except arsenic, which is distinctly un- 

 favorable to its development. 



The chlorosis of plants, P. MAzf: (Compt. Rend. Soc. Biol. [Paris}, 77 (1914), 

 No. 31, pp. 539-541). — Summarizing some of his investigations relating to 

 chlorosis (E. S. R., 31, p. 221), the author found that this disease could be in- 

 duced in maize by a lack of iron, sulphur, manganese, etc. For chlorosis caused 

 by a lack of iron, providing this substance in solution to chlorotic leaves quickly 

 restored their green color. Chlorosis due to a lack of magnesium was less 

 easily controlled, indicating that there are several kinds of chlorosis. The lack 

 of iron is said to be the most common form of the trouble, and this is usually 

 brought about by the presence of large amounts of carbonate of lime in the soil, 

 which check the absorption of iron. Chlorosis due to a lack of manganese is 

 considered to be of a special type, although it too is influenced by alkalinity of 

 soils. 



It is said that other alkaline carbonates, as those of potassium and sodium, 

 produce similar effects on the absorption of iron, etc., by plants. Exudation 

 from diseased cells is said to cause chlorosis, and this action is considered to be 

 more or less specific for the different kinds of plants studied. 



The influence of fl.uorin upon vegetation, A. Gautier {Compt. Rend. Acad. 

 Sci. [Paris], 160 {1915), No. 6, pp. 194, 195). — It is stated that in experiments 

 with fluorin in the nutritive medium it was found that an inhibitive or unfavor- 

 able influence was exerted upon very few plants, many more showing an in- 

 crease of growth, flowering, and bearing, and some showing no effect from 

 fluorin. Mustard gave a ninefold gain as regai'ds seed output under the influ- 

 ence of fluorin, and several other plants named gave analogous results. 



Investigations on the resistance of growing plants to hydrocyanic acid 

 fumigation, J. Cotte {Compt. Rend. Soc. Biol. [Paris], 77 {1914), No. 22, pp. 

 185-187). — In order to test the injury by hydrocyanic acid gas fumigation on 

 plants, the author experimented with wheat, castor beans, and garden nas- 

 turtiums grown in pots and subjected to different strengths of hydrocyanic acid 

 gas for different periods of time at a nearly uniform temperature of 16° C. 

 (60.8° F.). The gas was generated by the action of dilute sulphuric acid on 

 potassium cyanid. The quantities of potassium cyanid used per cubic meter 

 of space were 12.5, 15.63, 23.25, and 39.06 gm., respectively, amounts which are 

 in excess of those usually recommended for use in fumigation. 



Wheat plants were only slightly affected when exposed for one hour to the 

 action of 12 gm. potassium cyanid per cubic meter, and for the complete destruc- 

 tion of the plants a sojourn of two hours exposed to the action of 39 gm. potas- 

 sium cyanid was required. The castor bean plants showed some lesions where 

 15 gm. of the cyanid was used per cubic meter, and at 23 gm. the plans sue- 



