Page:Popular Science Monthly Volume 7.djvu/786

766 he was stung thrice, and the pain was considerably less, though the swelling was still extensive. At the end of the next week he had had eighteen stings, and by the close of the third week thirty-two stings. After the twentieth sting there was very little swelling or pain, only a slight itching sensation, with a small amount of inflammation in the immediate neighborhood of the part stung, which did not spread farther.

Influence of Cobra-Poison on Ciliary Action.—In the Monthly Microscopical Journal for June is given a record of experiments made by Drs. Brunton and Fayrer upon the influence of cobra-poison on ciliary action. Ciliated epithelium from a frog's mouth was treated with a solution of the poison, and examined under the microscope. The cilia were then in vigorous action. Ten minutes later this action was much diminished, and in twenty minutes it had ceased. Again, ciliated epithelium was placed under the microscope, one part being treated with water and the other with the poisoned solution. Ciliary action was at first vigorous in both, perhaps more so in that subjected to the poisoned solution. Eight minutes later, non-poisoned cilia still active, poisoned cilia very feeble. Ten minutes, non-poisoned cilia still active, poisoned very feeble. Fourteen minutes, non-poisoned cilia still active, poisoned cilia very languid. Twenty minutes, non-poisoned cilia still active, poisoned cilia perfectly inactive. From this it is evident that the poison first stimulates and then destroys the activity of the cilia. The action of the poison on vegetable protoplasm is very different. This subject was investigated by Mr. Darwin, who tested the action of cobra-poison on Drosera. A minute drop of the solution (one-quarter grain to two ounces water) acted powerfully on several glands of the drosera-leaf—more powerfully than fresh poison from an adder's fang. Oil immersing three leaves in ninety minims of the solution, the tentacles soon became inflated and the glands quite white, as by the action of boiling water. The leaves appeared to be killed, yet after eight hours' immersion they were placed in water, and after about forty-eight hours re-expanded. Having immersed a leaf in the solution for forty-eight hours, Mr. Darwin found that the protoplasm was then incessantly changing form, being unusually active. "Hence," says he, "I cannot doubt that this poison is a stimulant to the protoplasm" of plants.

Copper-poisoned Pastures.—It was observed by the late Prof. Buckland, the geologist, that the bones of cattle pastured in the vicinity of copper-works became diseased. This observation has been confirmed by his son, Frank Buckland, who has examined the skull of a cow, which had for three years grazed the copper-smoked grass. He describes the substance of the bone as much thickened and enlarged. Instead of the usual ivory-like smooth appearance of healthy bone, it appears to be eaten into minute pits. The lower jaw presents several hard, osseous excrescences, and the general appearance closely resembles that of bones affected by mercurial poisoning, one of the symptoms of which is a superficial deposit of rough, porous bone. Whether the mineral deposited on the grass in the vicinity of copper-works, and which is eaten by cattle, and subsequently absorbed into their system, be copper or arsenic, or arsenite of copper, Mr. Buckland is unable to determine at present, but he intends to have the substance analyzed by a competent chemist. The symptoms of the poisoning are stated as follows by a correspondent of Mr. Buckland: First, the beast appears dull, and its hair is dry; the eyes water, and the belly becomes tucked up; soon the beast shows signs of being in pain when moved; hard lumps rise on the legs and on the ribs; the bones of the head become enlarged, and the eyes appear sunken; the teeth become black and worn; lameness appears, sometimes in one leg only, at other times in all the limbs; in milch-cows the milk dries up.

Sensitiveness of Silver-Salts to Light.—In the American Journal of Science, for April, M. Carey Lea has a paper on "The Action of the Less Refrangible Rays of Light on Silver Iodide and Silver Bromide," in which the following propositions are maintained, viz.: 1. That these two salts of silver are sensitive to all the visible rays of the spectrum; 2. That silver iodide is more