Page:Sea and River-side Rambles in Victoria.djvu/46

27 warrants the presumption, that a highly poisonous fluid is injected at the same time, capable of arresting and destroying animal life.

At a recent meeting of the Dublin University Zoological and Botanical Association, Dr. M'Donnell stated in reference to the urticating organs of the Actiniæ and on the spasmodic action caused by them when suffered to touch the nerves of a frog prepared for electrical experiments, that at one time he had thought this was caused by electricity generated in these animals; but that further experiments and the use of a very delicate galvanometer had caused him to abandon this view, and to ascribe these movements to the local irritation caused by the poison contained in the cells of the Actiniæ.

These stinging properties are mentioned by various authors from Aristotle down to Johnston; but Mr. Lewes agrees with Sir John Dalyell, that the tentacles do not secrete any poison, as from experiments repeatedly tried, he finds that animals frequently escape unhurt after being seized by the tentacles; probably, however, it may be present to a greater degree in some species than in others, and more fully developed at certain seasons; hence the diversity of opinion amongst so many really observant men. The grasp of the Hydra is, as Johnston remarks, "eminently poisonous," small water-worms which this polyp is only able to attack, are so tenacious of life, that they may be cut to pieces without their seeming to receive any material injury or pain; yet the poison of the Hydra instantly extinguishes every principle of life