394 Effect of Salicylic Aldehyde on Plauts [April-July. 



were quite harmful. With 25 p.p.m. growth was reduced from 100 

 to yy, or 22, percent. With 50 p.p.m. growth was reduced from 100 

 to 61, or 39 percent. In amounts of 100 and 200 p.p.m, the plants 

 were killed. 



Effect on corn. The action of salicyhc aldehyde in soil and 

 also in sand was tested as to its effect on corn. The aldehyde was 

 added to a clay soil and to pure quartz sand in amounts of 50 p.p.m. 

 One pot each of the soil and sand untreated was run as a check. 

 Corn was planted May 23d and it grew until June 20th. One corn 

 plant was used in each pot containing soil and two plants in the pots 

 containing sand. 



A photograph of the plants is shown in Fig. 6 (Plate 7). The 

 first two pots contain soil and the last two sand. Number 2 in each 

 case is treated with salicylic aldehyde. Growth in the treated pots 

 is Seen to be much smaller than that in the check pots. The effect of 

 the salicylic aldehyde in the sand is seen to be greater than in the 

 clay soil. 



The green weights of the plants were taken at the termination 

 of the experiment. The salicylic aldehyde was found to have re- 

 duced growth in the clay soil from 100 to 76, or 24 percent, and in 

 sand from 100 to 40, or 60 percent. The harmful effect was more 

 marked in the quartz sand than in the clay soil, which is probably 

 due to the absorptive power of the clay, being far greater than that 

 of the sand, and perhaps also to the higher nutritive value of the soil 

 in comparison with the pure sand. 



Effect on clover The clover was grown in an ordinary flower 

 pot holding 6 Ibs. of soil; a good loam soil — the Hagerstown loam. 

 One pot was untreated, the other had a total of 100 p.p.m. of the 

 salicylic aldehyde added to it. 



When the soil was potted, 50 p.p.m. of the aldehyde were added, 

 and clover then sown, 0.5 gram of seed per pot. Later, when the 

 clover was up, 25 p.p.m. more of the aldehyde were added in Solu- 

 tion through a funnel passing into the soil nearly to the bottom of 

 the pot, thus avoiding direct contact with the tops or roots of the 

 clover. Three weeks later another 25 p.p.m. were added in the 

 same manner. The experiment lasted from April I2th to June 2 ist, 

 19 12. From the beginning the effect of the aldehyde on the clover 

 was noticeable. 



