2 BULLETIN 108, U. S. DEPARTMENT OF AGRICULTURE. 



aqueous solution of sodium bisulphite. The bisulphite solution 

 was separated from the ether, strongly acidified with sulphuric acid, 

 and air blown through to remove sulphur dioxide. This solution 

 was then shaken with several portions of fresh ether, the ether 

 extracts combined, and the ether removed by evaporation over a 

 small volume of water. The solution remaining was filtered from 

 a small quantity of resinous insoluble material and as thus obtained 

 was a slightly colored solution having an aromatic odor and the 

 properties of a solution of salicylic aldehyde. On slow evaporation 

 of the water there was left a yellow oil, soluble in water with some 

 difficulty, but very soluble in alcohol or ether. The water solution 

 developed a pink color in fuchsine aldehyde reagent almost immedi- 

 ately and gave an intense violet color with ferric chloride. When 

 treated with phenylhydrazine, a precipitate was formed which on 

 recrystallization from alcohol was in the form of yellow leaflets that 

 melted at 143°, the characteristic form and melting point of the 

 phenylhydrazone of salicylic aldehyde. The separation of this 

 compound from ether solution by an' aqueous solution of sodium 

 bisulphite and the color produced with fuchsine reagent fix it as an 

 aldehyde. The general properties of the compound and the forma- 

 tion of the hydrazone melting at 143° are sufficient to identify it as 

 salicylic aldehyde. 



As the large sample of soil collected was used up in the above 

 isolation and identification of some of its organic constituents, a 

 second shipment of the soil was secured and sufficient salicylic alde- 

 hyde obtained to make some tests of its action on plants. 



The effect of the soil aldehyde was tested on wheat by growing 

 the plants in water cultures. An experiment was made with the 

 aldehyde dissolved in pure distilled water. The wheat was grown 

 in water in culture jars holding 250 c. c. One jar contained pure 

 distilled water, and the second contained the water in which was 

 dissolved the aldehyde separated from the soil. The. plants grew 

 for two weeks. The aldehyde was quite harmful, reducing growth 

 about 37 per cent. Another experiment was made, using a good 

 nutrient solution with and without the substance. The aldehyde 

 from the soil was extremely harmful, even in the good nutrient 

 solution; the green weight of the plants was reduced 40 per cent. 

 These experiments with the salicylic aldehyde extracted from the 

 soil on growth are shown in Plate I, figure 1. The plants show the 

 harmful effect of the substance on growth. It will be seen that 

 both tops and roots in nutrient solution and in distilled water are 

 badly affected by the presence of the salicylic aldehyde. 



Having thus demonstrated the harmful action of this substance 

 when isolated from a soil, there remains a further study of the action 

 of this compound on various plants and in various culture solutions, 



