348 Journal of Agricultural Research voi. xviii. No. 7 



Six wheat seedlings were introduced into these jars and held in place 

 through slits in the corks by rubber bands. The seedlings had been 

 sprouted in pans of distilled water on floating perforated aluminum disks and 

 allowed to grow for three days, or until they were about 10 cm. long, before 

 being placed in the solutions. At the same time a similar set of jars, 

 with small holes drilled in the bottom for drainage, were filled with quartz 

 sand and planted with wheat seed. These sand cultures were watered 

 almost continuously during the day with sodium-chlorid solution of the 

 same strength as that used in the corresponding water culture. By 

 forcing a large amount of solution through each jar the concentration of 

 the solution in the sand was kept fairly constant. This was frequently 

 checked by titrating the solution before and after it passed through 

 the sand. 



When the plants were 8 days old they were removed and photo- 

 graphed. The plants grown in solution are shown in Plate 38, A, and 

 those grown in sand in Plate 38, B. It will be seen from Plate 38, A, 

 that the toxic action of sodium chlorid manifests itself, especially upon 

 the root development, in all the concentrations tried. This was not true 

 in the sand culture, in which an increase in growth was noticed up to a 

 concentration of i ,000 parts per million. In comparing the two illus- 

 trations it will be noticed also that the higher concentrations were 

 more toxic in the sand than in the solution cultures. This was probably 

 due to the fact that sand cultures were started from the seed, while the 

 solution cultures were started from seedlings 3 days old, the plant being 

 apparently more sensitive to sodium chlorid during the first few days 

 of its growth. 



This necessitated a change in the method of sprouting the seedlings. 

 In all the experiments hereafter to be described the seedlings were 

 sprouted in the same concentration of the solution as that in which they 

 were afterwards to be placed. 



SERIES 2 



The next experiment was begun on February 26, with the following 

 solutions : 



SOLDTION NO. CONCBNTRATION OP SOLUTION. 



1 Distilled water. 



2 500 parts per million of sodium chlorid. 



3 1,000 parts per million of sodium chlorid. 



4 1,500 parts per million of sodium chlorid. 



5 2,000 parts per million of sodium chlorid. 



6 3,000 parts per million of sodium chlorid. 



7 4,000 parts per million of sodium chlorid. 



Large enameled pans holding about 3 liters were filled with the solu- 

 tions of the different concentrations, and perforated aluminum disks 

 were floated in them. Wheat seeds were sprouted upon the disks. 



