152 DROSERA ROTUNDIFOLIA. (Cuar. VIII. 
3 hrs. 45 m. tentacles closely inflected, with the glands blackened. 
After 22 hrs. still closely inflected, and the leaves flaccid. Placed in 
“pure water, next day evidently dead. A rapid poison. 
Nickel, Chloride of —Three leaves immersed in ninety minims of a 
solution of one part to 487 of water; in 25 m. considerable inflection, 
and in 3 hrs. all the tentacles closely inflected. After 22 hrs. still 
closely inflected; most of the glands, but not all, blackened. The 
leaves were then placed in water; after 24 hrs. remained inflected; 
were somewhat discoloured, with the glands and tentacles dingy red. 
Probably killed. 
Cobalt, Chloride of.—Three leaves immersed in ninety minims of a 
solution of one part to 437 of water; after 23 hrs. there was not a 
trace of inflection, and the glands were not more blackened than oftem 
occurs after an equally long immersion in water. 
Platinum, Chloride of.—Three leaves immersed in ninety minims of 
a solution of one part, to 487 of water; in 6 m. some inflection, which 
became immense after 48m. After 3 hrs. the glands were rather pale. 
After 24 hrs. all the tentacles still closely inflected; glands colourless; 
remained in same state for four days; leaves evidently killed. 
Concluding Remarks on the Action of the foregoing Salis——Of 
the fifty-one salts and metallic acids which were tried, 
twenty-five caused the tentacles to be inflected, and twenty- 
six had no such effect, two rather doubtful cases occurring in 
each series. In the table at the head of this discussion, the 
salts are arranged according to their chemical affinities; but 
their action on Drosera does not seem to be thus governed. 
The nature of the base is far more important, as far as can be 
judged from the few experiments here given, than that of the 
acid; and this is the conclusion at which physiologists have 
arrived with respect to animals. We see this fact illustrated 
in all the nine salts of soda causing inflection, and in not 
being poisonous except when given in large doses; whereas 
seven of the corresponding salts of potash do not cause 
inflection, and some of them are poisonous. Two of them, 
however, viz. the oxalate and iodide of potash, slowly in- 
duced a slight and rather doubtful amount of inflection. 
This difference between the two series is interesting, as Dr. 
Burdon Sanderson informs me that sodium salts may be 
introduced in large doses into the circulation of mammals 
without any injurious effects; whilst small doses of potas- 
sium salts cause death by suddenly arresting the movements 
of the heart. An excellent instance of the different action of 
the two series is presented by the phosphate of soda quickly 
causing vigorous inflection, whilst phosphate of potash is 
