I9I4] 



/. /. Skinner 



391 



culture of dist. water without salicylic aldehyde was included in the 

 test and used as a control. The cultures grew from May 4th to 

 May i6th, 19 12. It became at once apparent that the saHcyHc alde- 

 hyde was very harmful to the seedhng wheat, even in the lowest 

 conc. of 10 p.p.m. The appearance of the series of plants on the 

 6th day is shown in Fig. i (Plate 6). In the culture Solution con- 

 taining 10 p.p.m., growth was reduced 31 percent; in the 25 p.p.m. 

 Solution growth was reduced 69 percent; with 50, 100 and 200 

 p.p.m. the plaiits were killed. 



Effect on corn. The effect of salicylic aldehyde on corn plants 

 was tested by growing the corn in nutrient solutions of calcium acid 

 phosphate, sodium nitrate and potassium sulphate, with and without 

 salicylic aldehyde. The aldehyde was used in amounts of 10, 25, 

 100, and 200 p.p.m. One corn plant was used in each culture jar 

 containing 250 c.c. of the Solution. The plants were germinated 

 and put in the Solution when they were about i^^ in. high. The 

 corn grew in the solutions from May 26th to June 20th, 1912. A 

 photograph of the cultures is shown in Fig. 2 (Plate 6), taken when 

 the plants had been growing for 10 days. The harmfulness of this 

 substance to corn is clearly shown. The efifect was very noticeable, 

 even in the culture containing 10 p.p.m. In the culture containing 

 200 p.p.m. there was very little growth; the plants were almost dead. 



In Table i are given the green weights of the plants, taken when 

 the experiment was concluded. The last column gives the relative 

 growth. 



TABLE I 



Effect of salicylic aldehyde on corn in nutrient solutions of calcium acid 

 Phosphate, sodium nitrate and potassium sulphate 



The figures in Table i show the decreased growth due to the 

 salicylic aldehyde. Ten p.p.m. reduced growth from 100 to 60 or 

 40 percent; 50 and 100 p.p.m. were also extremely harmful; there 

 was very little growth in the presence of 200 p.p.m. 



