540 ScHREINER & SKINNER: EFFECT OF GUANIDIN ON PLANTS 
For the first few days no difference was noticeable between 
the control and the guanidin set. About the fifth day bleached 
spots appeared in the leaves in some of the cultures, producing an 
effect like a plant disease. The diseased spots on the leaves spread 
and became larger and more numerous. The spots appeared 
first on a few cultures, but when the cultures were arranged in 
the order of their composition the reason for this became evident. 
The guanidin effect showed itself first in the cultures high in 
nitrate and then spread to those lower in nitrate, until the series 
of no nitrate content was reached. In this series the guanidin 
effect was scarcely discernible. As the plants grew older, the 
guanidin effect became more and more marked; the bleached spots 
anidin, series B 
Fic. 1. Effect of guanidin on wheat plants; series A without gu 
with guanidin. 
coalesced and appeared most marked in the lower part of the 
leaves; the leaves broke finally, presenting on the whole an effect 
similar to that produced by a wilt disease and accompanied with 
considerable bleaching of the green parts of the plant. bees 
at least, was the effect in all of the cultures containing nitrate 
and was the more marked the higher the nitrate content. The 
series containing no nitrate whatever retained its green color and 
was not subject to collapse or wilting, although here and there 
some bleached spots appeared. 
