1899] TOXIC EFFECT OF DELETERIOUS AGENTS 381 
HYDROXIDS. 
As it is quite impossible to handle solutions of hydroxids in 
an ordinary atmosphere without a greater or less loss by neutral- 
ization by the CO, of the air, the following toxic values of 
potassium hydroxid and ammonia must be somewhat less than 
their absolute toxic value. This source of error was reduced as 
much as possible by rapid handling in making the cultures. 
Potassium hydroxid, KOH; 77 (?), 166, 282. In no other 
case was it found so difficult to determine where to place the 
- coefficient of injury, pe retarded germination in all cases, and 
| Ld Hn 
sane and even eee: 
an injurious influence. 
At 24 and 36 hours, however, the cultures presented a very 
with some forms 
(CEdocephalum) showed 
n 
different appearence. Cultures in concentration showed a 
2048 
heavier mycelium than the checks, and with stronger concen- 
trations this stimulation of mycelial development was more 
n n : 
— or — concentration. 
Marked until the climax was reached in ba as 
. . . . . . 
As 7p Proved the average inhibiting point, it will be seen 
that, as with the acids, the maximum stimulation of mycelial 
! development occurred about two removes from the limit of ger- 
: Mination, or, in other words, in solutions containing one fourth 
: the Concentration of the agent inhibiting the germination of the 
‘Pores. The retardation of fruiting in the stimulated cultures 
_ Was very marked, and suggested the query as to whether they 
Were both due to the same cause, or whether one was a result of 
E the Other. It is well known that with the higher plants vias 
_ Pression of fruiting tends to force the energies of the plant into 
Vegetative lines, and it is not apparent to the writer why this 
Pout not be trué: of the fungi also. On the other hand, 
Strytis, which did not fruit, showed nearly or quite as great a 
‘mulation of mycelial development as any other form. 
