SCHREINER & SKINNER: EFFECT OF GUANIDIN ON PLANTs 541 
In FIG. I are shown the two sets of cultures. A is the normal 
or control set and B the guanidin set. The distinctly destructive 
effect of the guanidin is apparent in the blighted appearance of 
set B in striking contrast to the fine growth in the control cultures, 
which is even more marked than the photograph can show because 
of the deep green color of the normal set contrasted with the 
bleached appearance of the guanidin set. 
Fic. 2. Effect of guanidin on wheat plants. Nearer view of series B in FIG. I. 
In FIG. 2 a nearer and better view is had of this guanidin set. 
The plants are arranged according to the composition of their 
culture solutions, thus forming a triangle. By this arrangement 
the highest nitrate culture appears at N, the highest phosphate 
culture at P, and the highest potash culture at K. Itis apparent 
that the poorest plant development occurs in those cultures high in 
nitrate but is distinctly noticeable in every culture except in the 
line of cultures from P to K, which is the series containing no 
nitrate. The plants in this line of cultures are firm and erect, 
as can be seen in the photograph. In actuality this difference is 
accentuated by the nearly normal green color of this series, whereas 
