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Page:Popular Science Monthly Volume 38.djvu/147

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its prey. It has been known to allow itself to be carried into the air by a large fly that it has attacked rather than relinquish its hold. The female tarantula lays from nine hundred to a thousand eggs in a season, and shows considerable maternal care. She has never been known to abandon her offspring until they are able to take care of themselves. She hatches two broods in the year, in spring and autumn, and has been known to hatch three. The eggs are deposited after they are hatched within a bag or cocoon almost as thick as paper, which the mother makes for them, and then fastens to the end of her body. When the young ones are excluded from their shells within the cocoon they remain in confinement until the female, instinctively knowing their maturity, bites open the bag and sets them free. The young of web-making spiders, after leaving the egg, immediately commence weaving, but the young tarantulas (leading a vagrant life and having no web), being incapable of protecting themselves, remain for about a fortnight with the mother. This formerly gave rise to a belief that they derived their nourishment from her body.


Poisonous Spiders—. It does not seem to be generally known that spiders secrete a poison of a very active nature, the effects of which are similar to those produced by snake poisons. The bite of the common house-spider is quickly fatal to flies and other insects on which it preys; when a fly is bitten by a spider its whole body seems seized by violent convulsive twitchings, and death generally occurs after a few minutes. The spider's poison issues from a sac and duct at the base of its mandibles; it closely resembles the venomous matter secreted by scorpions, and is a transparent fluid, containing traces of formic acid and albumin. The spider is provided with a most effective apparatus for injecting its poison, consisting of modified mandibles called falces, the last joint of which has a hard curved fang, with a fissure near the point. The muscles used in closing the mandibles also press upon the poison-gland, causing the poison to be expelled through the fissure into the wound, and thence into the circulation of the victim. The most venomous spider known is a little fellow confined to New Zealand, called by the native inhabitants "Katipo," its bite not infrequently causing chronic illness or death. Mr. W. H. Wright describes the case of a person bitten by the katipo on the shoulder. "The part bitten rapidly became swollen and looked like a large nettlerash wheal. About an hour afterward the patient, could hardly walk; the respiration and circulation were both affected, followed by prolonged muscular prostration. The patient, however, recovered in two or three days."


African Jumpers.—Dr. Bennett, of Griqualand, writes an account of a peculiar nervous affection which is met with among the Griquas and other natives and individuals of mixed descent living in Griqualand. He suggests that perhaps the affection is similar to that prevalent among the French Canadians and known by the name of "Jumpers," which was described by Dr. G. M. Beard in The Popular Science Monthly for December, 1880. Dr. Bennett says: "The affection is entirely confined to the male sex, and I have never seen or heard of a case in the female. The victims of this strange form of neurosis go through the most extraordinary and grotesque antics on the slightest provocation. A whistle, a touch, a shout—anything, in fact, suddenand unexpected—will 'set them going.' Some will stiffen their limbs, make hideous grimaces, and waltz about as if they had no joints in their body. Others will jump wildly about like dancing dervishes, imitating the particular sound that had acted as an exciting cause. Some, again, will make use of the most obscene expressions on a transient impulse, correcting themselves immediately afterward and expressing their regret for having used such language; while others, on the spur of the moment, will do anything they are told to do. If they should happen to have a piece of tobacco in their hand and one should suddenly shout ' Throw it away! ' they will do so at once, running away for a short distance and trembling all over their body. I remember one case in particular. It was that of a young man, a mason by trade. He had been handed a piece of tobacco, and the person who handed it to him shouted out suddenly, ' Throw it away; it is a snake! ' He first danced about wildly for a short time, and then ran away as fast as he was able; but he had not gone far when