546 SCHREINER & SKINNER: EFFECT OF GUANIDIN ON PLANTS 
that other nitrogenous compounds do not share this property 
with the nitrate. 
To solution no. 41, containing 16 parts per million phosphate, 
32 parts per million nitrate, and 32 parts per million potash, 25 
parts per million of guanidin were added, and wheat seedlings were 
grown in this solution as well as in a control without guanidin. 
A similar set of cultures was prepared with and without guanidin, 
but with this difference that the nitrate was omitted entirely 
and an equivalent amount of nitrogen in the form of asparagin 
was added to the culture solution. The plants grew from March 
10 to March 23, 1911. 
The characteristic effects of guanidin were noticed in the 
culture containing nitrate but did not appear in the culture con- 
taining asparagin. The appearance of the cultures is shown in 
y . ient 
Fic. 6. Effect of guanidin with nitrogen in different forms; no. 1: nn < 
solution containing sodium nitrate; no. 2, same plus guanidin; no. 3, nutrient — 
containing asparagin; no. 4, same plus guanidin. 
FIG. 6, where no. 1 is the control with nitrate and no. 3 the control 
with asparagin. No. 2 and 4 are the guanidin cultures to be 
compared with each other and with their respective controls. No. 
2 shows the wilting effect of the guanidin as well as the decreased 
growth. The colors of the various cultures brought out the differ- 
ence even more strikingly. The green weights given in TABLE il 
bear out the same point. 
