174 DROSERA ROTUNDIFOLIA. [Cuar. 1X, 
pure glycerine is poisonous, and if applied in very minute quantities 
to the glands of the outer tentacles causes their inflection. 
The Effects of Immersion in Water and in various Solutions on 
the subsequent Action of Phosphate and Carbonate of Ammonia.— 
We have seen in the third and seventh chapters that immersion in 
distilled water causes after a time some degree of aggregation of the 
protoplasm, and a moderate amount of inflection, especially in the 
case of plants which have been kept at a rather high temperature. 
Water does not excite a copious secretion of mucus. We have here to 
consider the effects of immersion in various fluids on the subsequent 
action of salts of ammonia and other stimulants. Four leaves which 
had been left for 24 hrs. in water were given bits of meat, but did not 
clasp them. Ten leaves, after a similar immersion, were left for 24 hrs, 
in a powerful solution (1 gr. to 20 oz.) of phosphate of ammonia, and 
only one showed even a trace of inflection. Three of these leaves, on 
being left for an additional day in the solution, still remained quite 
unaffected. When, however, some of these leaves, which had been 
first immersed in water for 24 hrs., and then in the phosphate for 
24 hrs. were placed in a solution of carbonate of ammonia (one part 
to 218 of water), the protoplasm in the cells of the tentacles became 
in a few hours strongly aggregated, showing that this salt had been 
absorbed and taken etfect. 
A short immersion in water for 20 m. did not retard the subsequent 
action of the phosphate, or of splinters of glass placed on the glands; 
but in two instances an immersion for 50 m. prevented any effect from 
a solution of camphor. Several leaves which had been left for 20 m. 
in a solution of one part of white sugar to 218 of water were placed in 
the phosphate solution, the action of which was delayed; whereas a 
mixed solution of sugar and the phosphate did not in the least interfere 
with the effects of the latter. Three leaves, after being immersed for 
20 m. in the sugar solution, were placed in a solution of carbonate of 
ammonia (one part to 218 of water); in 2 m. or 3 m. the glands 
were blackened, and after 7 m. the tentacles were considerably inflected, 
so that the solution of sugar, though it delayed the action of the 
phosphate, did not delay that of the carbonate. Immersion in a 
similar solution of gum arabic for 20 m. had no retarding action on 
the phosphate. Three leaves were left for 20 m. in a mixture of one 
part of alcohol to seven parts of water, and then placed in the 
phosphate solution: in 2 hrs. 15 m. there was a trace of inflection in 
one leaf, and in 5 hrs. 80 m. a second was slightly affected; the 
inflection subsequently increased, though slowly. Hence diluted 
alcohol, which, as we shall see, is hardly at all poisonous, plainly 
retards the subsequent action of the phosphate. 
It was shown in the last chapter that leaves which did not become 
inflected by nearly a day’s immersion in solutions of various salts and 
acids behaved very differently from one another when subsequently 
placed in the phosphate solution. I here give a table summing up 
the results. 
