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19 
for the weaker solutions, with the exception of the seeds treated for 
fifteen minutes, it was only after the seventh day that a considerable 
portion germinated. Germination continued until the ninth and tenth 
days, and in some cases until the fifteenth day, when the test was ter- 
minated. In the case of the stronger solutions the delay in germinating 
is still more apparent, in some cases not a seed sprouting before the 
sixth day after the treatment, at which time nearly all the check plants 
were up. 
The character of the plants grown from seed treated with the weaker 
solutions was not perceptibly different from that of plants from seed 
which received no treatment. When, however, the stronger solutions 
were used some very marked effects were noticeable, the most evident 
of which, aside from destroying or greatly retarding germination, was 
in the root development. 
EFFECT OF COPPER SULPHATE ON THE ROOT SYSTEM OF PLANTS. 
The corrosive effect of copper sulphate upon the root system of seed- 
lings has already been noticed by Nobbe, Arthur, and others (pp. 9,13). 
Some of the plants grown from seed treated for three hours in a 2 per 
cent solution and most of those from the 5 and 10 per cent solutions 
were entirely without primary roots at the end of the experiments. 
. Unsprouted seed after lying for eight days in the sand was examined 
and the radicle end of the embryo was found to be dead and black. 
In many of the sprouted seeds examined the slightly developed 
primary root was eroded or so softened as to break down easily under 
the slightest pressure. Plants whose plumules had grown to 10 to 
15 cm. in height had no roots other than the rotted remnants of the 
primary roots. All such plants withered and died as soon as the 
reserve material of the seed was exhausted. In other cases second- 
ary roots by which the plant could be sustained were developed from 
the first few nodes, often appearing as far as an inch from the seed. 
In nearly every case examined the roots developed from the primary or 
embryonal node were unable to push their way through the glumes of 
the seed, and remained as more or less disintegrated remnants. How- 
ever, after two or three weeks but little difference in general appear- 
ance could be seen between plants developing secondary roots and those 
grown from seed which had received no treatment. 
EFFECT OF COPPER SULPHATE ON THE GROWTH OF AERIAL PARTS 
OF PLANTS. 
In the aerial portion of the plants the effect of the stronger solutions 
was apparent in the retarded growth and in the difference of color. 
At the expiration of ten days no difference was noticeable between the 
plants from the untreated and treated seed in cases where only the 
weaker solutions had been used, but in plants from seed which had 
