ORGANIC CONSTITUENTS. 31 



III. Plants grown in 50 parts per million potash solution. (Plumule-)- rootlet.) 



GROWN IN DISTILLED WATER (CONTROL). 



IV. Plants grown in 150 parts per million potash solution. (Plumule-)- rootlet.) 



GROWN IN DISTILLED WATER (CONTROL). 



V. Plants grown in 100 parts per million nitrate solution. (PI umule-f rootlet.) 



GROWN IN DISTILLED WATER (CONTROL). 



