Poison from the Fang of a Living Adder.—­Minute drops were placed on the glands of many tentacles; these were quickly inflected, just as if saliva had been given them, Next morning, after 17 hrs. 30 m., all were beginning to re-expand, and they appeared uninjured.

Poison from the Cobra.—­Dr. Fayrer, well known from his investigations on the poison of this deadly snake, was so kind as to give me some in a dried state.  It is an albuminous substance, and is believed to replace the ptyaline of saliva.* A minute drop (about 1/20 of a minim) of a solution of one part to 437 of water was applied to the secretion round four glands; so that each received only about 1/38400 of a grain (.0016 mg.).  The operation was repeated on four other glands; and in 15 m. several of the eight tentacles became well inflected, and all of them in 2 hrs.  Next morning, after 24 hrs., they were still inflected, and the glands of a very pale pink colour.  After an additional 24 hrs. they were nearly re-expanded, and completely so on the succeeding day; but most of the glands remained almost white.

Half-minims of the same solution were placed on the discs of three leaves, so that each received 1/960 of a grain (.0675 mg.); in

Dr. Fayrer, ‘The Thanatophidia of India,’ 1872, p. 150. [page 207]

4 hrs. 15 m. the outer tentacles were much inflected; and after 6 hrs. 30 m. those on two of the leaves were closely inflected and the blade of one; the third leaf was only moderately affected.  The leaves remained in the same state during the next day, but after 48 hrs. re-expanded.

Three leaves were now immersed, each in thirty minims of the solution, so that each received 1/16 of a grain, or 4.048 mg.  In 6 m. there was some inflection, which steadily increased, so that after 2 hrs. 30 m. all three leaves were closely inflected; the glands were at first somewhat darkened, then rendered pale; and the protoplasm within the cells of the tentacles was partially aggregated.  The little masses of protoplasm were examined after 3 hrs., and again after 7 hrs., and on no other occasion have I seen them undergoing such rapid changes of form.  After 8 hrs. 30 m. the glands had become quite white; they had not secreted any great quantity of mucus.  The leaves were now placed in water, and after 40 hrs. re-expanded, showing that they were not much or at all injured.  During their immersion in water the protoplasm within the cells of the tentacles was occasionally examined, and always found in strong movement.

Two leaves were next immersed, each in thirty minims of a much stronger solution, of one part to 109 of water; so that each received 1/4 of a grain, or 16.2 mg; After 1 hr. 45 m. the sub-marginal tentacles were strongly inflected, with the glands somewhat pale; after 3 hrs. 30 m. both leaves had all their tentacles closely inflected and the glands white.  Hence the weaker solution, as in so many other cases, induced