completely re-expanded, but the glands were much discoloured.  Hence this salt is not poisonous in any high degree.  The different action of the three foregoing salts of quinine is singular.

Digitaline.—­Half-minims of a solution of one part to 437 of water were placed on the discs of five leaves.  In 3 hrs. 45 m.  Some of them had their tentacles, and one had its blade, moderately inflected.  After 8 hrs. three of them were well inflected; the fourth had only a few tentacles inflected, and the fifth (an old leaf) was not at all affected.  They remained in nearly the same state for two days, but the glands on their discs became pale.  On the third day the leaves appeared much injured.  Nevertheless, when bits of meat were placed on two of them, the outer tentacles became inflected.  A minute drop (about 1/20 of a minim) of the solution was applied to three glands, and after 6 hrs. all three tentacles were inflected, but next day had nearly re-expanded; so that this very small dose of 1/28800 of a grain (.00225 mg.) acts on a tentacle, but is not poisonous.  It appears from these several facts that digitaline causes inflection, and poisons the glands which absorb a moderately large amount.

Nicotine.—­The secretion round several glands was touched with a minute drop of the pure fluid, and the glands were instantly blackened; the tentacles becoming inflected in a few minutes.  Two leaves were immersed in a weak solution of two drops to 1 oz., or 437 grains, of water.  When examined after 3 hrs. 20 m., only twenty-one tentacles on one leaf were closely inflected, and six on the other slightly so; but all the glands were blackened, or very dark-coloured, with the protoplasm in all the cells of all the tentacles much aggregated and dark-coloured.  The leaves were not quite killed, for on being placed in a little solution of carbonate of ammonia (2 grs. to 1 oz.) a few more tentacles became inflected, the remainder not being acted on during the next 24 hrs.

Half-minims of a stronger solution (two drops to 1/2 oz. of water) were placed on the discs of six leaves, and in 30 m. all those tentacles became inflected; the glands of which had actually touched the solution, as shown by their blackness; but hardly any motor influence was transmitted to the outer tentacles.  After 22 hrs. most of the glands on the discs appeared dead; but this could not have been the case, as when bits of meat were placed on three of them, some few of the outer tentacles were inflected in 24 hrs.  Hence nicotine has a great tendency to blacken the glands and to induce aggregation [page 204] of the protoplasm, but, except when pure, has very moderate power of inducing inflection, and still less power of causing a motor influence to be transmitted from the discal glands to the outer tentacles.  It is moderately poisonous.