1914] 



/. /. Skinner 



393 



Ten and 25 p.p.m. materially reduced the growth, while 50 p.p.m. 

 killed the plants. Cultures strenger than 50 p.p.m. are not shown. 



When weighed at the termination of the experiment, growth in 

 the culture containing 10 p.p.m. saHcyHc aldehyde was found to be 

 reduced 30 percent. With 25 p.p.m. growth was reduced 61 per- 

 cent. This shows that the aldehyde was quite harmful in small 

 amounts to young cabbage plants ; and in nutrient cultures contain- 

 ing 50, 100 and 200 p.p.m. of the aldehyde, the plants were killed. 



Effect on rice. When tested on rice seedlings in water and in 

 nutrient Solutions, salicylic aldehyde was also found to be harmful 

 to this crop. The dist. water solutions of 10 p.p.m. of salicylic alde- 

 hyde gave a depression of 16 percent in the green weight of the 

 plants. In the nutrient solutions, the 10 p.p.m. of salicylic alde- 

 hyde gave a depression of 15 percent in the green weight. 



SOIL CULTURES 



Effect on wheat. Experiments were made to study the effect 

 of saHcylic aldehyde in soil. Paraffined wire pots, holding approx- 

 imately one pound of soil, were used. The soil was a heavy clay 

 loam. Before potting, portions of the soil were treated with dif- 

 ferent amounts of salicylic aldehyde. Six wheat plants were grown 

 in each pot. The experiment was begun May 27th and discontinued 

 June 18. In Fig. 5 (Plate 7) are shown the plants as they appear 

 near the end of the experiment. This shows that the salicylic alde- 

 hyde was harmful. The final results are given in Table 3. 



TABLE 3 



Effect of salicylic aldehyde on wheat plants in soil 



As Seen from the data in Table 3, the aldehyde in amounts of 

 10 p.p.m. had no effect in the soil. Larger amounts than 10 p.p.m. 



