HARMFUL EFFECTS OF ALDEHYDES IN SOILS. 13 



portions of ether, the ether extract combined and shaken with a con- 

 centrated aqueous solution of sodium bisulphite, which will remove 

 aldehydes from the ether solution if present, by forming a water- 

 soluble combination with the sodium bisulphite. The bisulphite solu- 

 tion was separated from the ether, strongly acidified with sulphuric 

 acid, and air was blown through to remove the sulphur dioxide liber- 

 ated. This acidified solution, in which the aldehyde is now liberated 

 from its combination with the bisulphite, was then shaken with several 

 portions of fresh ether, the ether extracts combined, and the ether 

 removed by evaporation. There remained a small quantity of mate- 

 rial, often resinous or oily in appearance. 



This material was further purified by again taking up in water, 

 extracting with ether, and the ether solution, after filtering, allowed 

 to evaporate. Sometimes this operation was repeated. The purified 

 residue contains the aldehyde material, if present. 



This aldehyde material was treated with a small quantity of water. 

 The aqueous solution is frequently colored, and on evaporation a 

 yellow oil is often noticeable, as would be the case if salicylic aldehyde 

 were present. The odor of the latter is also sometimes observed, 

 although in other cases other odors are perceptible, suggesting other 

 aldehydes. 



The fuchsine reagent was added to a portion of the solution, and 

 to another portion a small amount of ferric chloride was added. 

 Salicylic aldehyde, as mentioned, gives a violet color with ferric 

 chloride and a pink color with the fuchsine reagent. Where both 

 these reactions were observed the soil was considered as containing 

 aldehyde. While the nature of the material is not thereby definitely 

 shown to be salicylic aldehyde, yet the manner of isolation with ether 

 and extraction therefrom with sodium 'bisulphite, together with the 

 reaction shown with the fuchsine reagent, show the material to be 

 an aldehyde, and the physical character of fluidity and the reaction 

 with ferric chloride make it quite probable that in most of these cases 

 salicylic aldehyde was under consideration. The amount obtained 

 did not permit of further identification than is here given, especially 

 as the main object was to determine the physiological property of the 

 extracted material. 



The main portion of the material remaining after making the above 

 tests was dissolved or mixed with 250 c. c. of pure distilled water and 

 the resulting liquid used as a culture for wheat seedlings in order to 

 test the physiological effect of the extracted material from the soil. 

 This was done with every soil examined, whether the above tests 

 were negative or positive. 



In order to study the presence of aldehydes in soils a number of 

 samples were tested. Included in this test were a number of soils 

 sent to this bureau from time to time by gardeners and greenhouse 



