542 SCHREINER & SKINNER: EFFECT OF GUANIDIN ON PLANTS 
all other cultures, in addition to the dilapidated condition, had a 
decidedly bleached appearance. 
The effect of the nitrate in increasing the harmful effect of 
guanidin is also shown by the weight of the tops taken at the 
termination of the experiment. In TABLE I the first column gives 
TABLE I 
EFFECT OF GUANIDIN ON GROWTH AS INFLUENCED BY NITRATE 
areal NH, it te re Green weight of cultures, grams Resign 
ertilizer mix! ure, ri Contro = 100 
parts per million Without guanidin bid Bey paces 4 
80 1.656 0.520 31 
55-65 42 4.178 T.990 47 
45-64 64 6.860 3.412 48 
6-63 56 9-449 5.031 53 
28-62 48 12.3590 6.874 55 
21-61 40 15.908 8.394 5? 
15-60 32 18.649 11.491 62 
10-59 24 21.601 13.602 62 
6-5 16 23.327 15.709 67 
Spay: 8 20.923 17.288 83 
1-56 o 16.156 15-195 94 
the series, the cultures of which have like nitrate content. The 
amounts of nitrate in each culture of these series are given in the 
second column. The third and fourth columns give the weight 
of the tops of the plants grown in the cultures without and with 
25 parts per million of guanidin carbonate. It is at once apparent 
that the guanidin is very harmful to growth. The total green 
weight of the 66 cultures in the normal set was 151.2 grams against 
only 99.5 grams in the guanidin set. Placing the normal at 100, 
the growth in the guanidin set becomes 66. The last column 
gives the relative growth in each of the series of uniform nitrate 
content in the set. The culture that contained 80 parts Pe 
million NH, as nitrate gave a relative weight of only 31 a 
decrease in growth of 69 per cent, whereas in the series of cultures 
that contained no nitrate the relative growth was 94, 4 decrease of 
only 6 per cent below the control. As shown in the table, the 
relative weight of tops obtained increased with decreasing nitrate 
content. 
The effect of guanidin on growth, and especially the har 
influence of the nitrate, was considered so remarkable, particul 
mful 
arly 
