I9I4] 



/. /. Skinner 



401 



tures were prepared as in the experiments already recorded. The 

 Solutions were composed of calcium acid phosphate, sodium nitrate 

 and potassium sulphate in different proportions. Salicylic aldehydc 

 was used in quantities of 10 p.p.m., and 100 mg. of calcium carbon- 

 ate were added to each culture, in the control set and in the salicylic 

 aldehyde set. The plants grew from Mar. 23d to April 4th — 12 

 days. The Solutions were changed every 3 days. The green 

 weights of the plants grown in Solution without and with salicylic 

 aldehyde are given in the two last columns of Table 8. 



TABLE 8 

 Effect of salicylic aldehyde in nutrient cultures containing calcium carbonate 



These data show that salicylic aldehyde was harmful even in 

 nutrient Solutions containing an excess of lime. The growth in each 

 culture with salicylic aldehyde was less than the corresponding cul- 

 ture containing no salicylic aldehyde. The total growth of the six 

 control cultures was 17.89 gm. against 13.4 gm. for the six salicylic 

 aldehyde cultures. Putting the normal at 100, the salicylic aldehyde 

 cultures become 75, a reduction in growth of 25 percent. 



In another test involving a much larger number of cultures of 

 different composition, essentially the same result was obtained. In 

 this case the growth was depressed 21 percent as an average. 



In the previous experiment involving a larger number of nutrient 

 Solutions without calcium carbonate, growth was reduced 27 per- 

 cent by salicylic aldehyde, used in the same conc. as for the experi- 

 ment with calcium carbonate. 



The roots of the plants were not as much stunted by the salicylic 

 aldehyde in the presence of calcium carbonate as they were in the 



