216 
may we not suppose* that the interstices of the walls of 
the glands were blocked up with the molecules of these five 
substances, so that they were rendered impermeable to water; 
for had water entered, we know from the ten trials that the 
phosphate would not afterwards have produced any effect? It 
further appears that the molecules of the carbonate of ammonia 
san quickly pass into glands which, from having been immersed 
for 20 m. in a weak solution of sugar, either absorb the phos- 
phate very slowly or are acted on by it very slowly. On the 
other hand, glands, however they may have been treated, seem 
easily to permit the subsequent entrance of the molecules of 
carbonate of ammonia. Thus leaves which had been immersed 
in a solution (of one part to 437 of water) of nitrate of potas- 
sium for 48 hrs.—of sulphate of potassium for 24 hrs.—and of 
the chloride of potassium for 25 hrs.——on being placed in a 
solution of one part of carbonate of ammonia to 218 of water, 
had their glands immediately blackened, and after 1 hr. their 
tentacles somewhat inflected, and the protoplasm aggregated. 
But it would be an endless task to endeavour to ascertain 
the wonderfully diversified effects of. various solutions on 
Drosera. 
Alcohol (one part to seven of water).—It has already been shown 
that half-minims of this strength placed on the discs of leaves 
do not cause any inflection; and that when two days afterwards 
the leaves were given bits of meat, they became strongly in- 
flected. Four leaves were immersed in this mixture, and two of 
them after 80 m. were brushed with a camel-hair brush, like the 
leaves in the solution of camphor, but this produced no effect. 
DROSERA BOTUNDIFOLIA. Cuar. IX. 
* See Dr. M. Traube’s curious 
experiments on the production of 
artificial cells, and on their per- 
meability to various salts, de- 
scribed in his papers: “Experi- 
mente zur Theorie der Zellenbil- 
dung und Endosmose,” Breslau, 
(866; and “Experimente zur 
physicalischen Erklarung der Bil- 
dung der Zellhaut, ihres Wachs- 
thums durch Intussusception,” 
Breslau, 1874. These researches 
perhaps explain my results. Dr. 
Traube commonly employed as a 
membrane the precipitate formed 
when tannic acid comes into con- 
tact with a solution of gelatine. 
By allowing a precipitation of 
sulphate of barium to take place 
at the same time, the membrane 
becomes “infiltrated” with this 
salt; and in consequence of the 
intercalation of molecules of sul- 
phate of barium among those of 
the gelatine precipitate, the mole- 
cular interstices in the membrane 
are made smaller. In this altered 
condition, the membrane no longer 
allows the passage through it of 
either sulphate of ammonia or 
nitrate of barium, though it re- 
tains its permeability for water 
and chloride of ammonia. 
