Page:The Atlantic Monthly, Volume 18.djvu/146

138 hold the smaller legs, the larger were in danger of being crushed, and the spider, fearing this, often disjointed them, according to the convenient, though loose habit of most Arachnida, crabs, and other articulates. It was also proposed to secure several spiders in the above manner upon the periphery of a wheel, the revolution of which would give a twist to their conjoined threads, carried through a common eyelet upon the spindle; but this can be accomplished without the inconvenience of whirling the spiders out of sight, by modifications of the apparatus which has always been used for twisting ordinary silk. It will probably be inferred from the above, that, in securing the spider, two points are to be considered; first, to prevent its escape, and second, so to confine the legs that it cannot reach with their tips either the silk or the spinners. Now the machine accomplished this by putting all the legs together in a vice, as it were, entailing upon the captive much discomfort and perhaps the loss of some of its legs, which, though eight in number, are each appropriated to a special use by their possessor.

So, abandoning the machine, I fell back upon a simple reel, and a modification of my little contrivance of the previous year; which was, to grasp the spider by all the legs, holding them behind her back, and to let her body down into a deep notch or slot cut in a thin card, the edges of which reached the constriction between the two regions of the body, the cephalothorax and abdomen; so that, when a second piece of card was let down upon it, the cephalothorax, with the legs of the spider, was upon one side of a partition, while on the other was the abdomen, bearing upon its posterior extremity the spinning organs. The head and horns of a cow to be milked are secured in a similar manner. By placing in a row, or one behind another, several spiders thus secured, a compound thread was simultaneously obtained from them, and wound upon a spindle of hard rubber.

By this means were produced several very handsome bands of bright yellow silk; but the time was so short, and the means of constructing and improving my apparatus so deficient, that I could procure no more than these few specimens, which were very beautiful, and shone in the sun like polished and almost translucent gold; but which, being wound upon a cylinder only an inch in diameter, and from several spiders at different times, could not be unwound, and so made of any further use.

I tried now to ascertain how much silk could be obtained from a single spider at once. It will be remembered that the first specimen, wound on Folly Island, was one hundred and fifty yards in length, and weighed one third of a grain. I now exhausted the supply of a spider for three days, using the same spindle, one inch in diameter, and turning this at the rate of one hundred and sixty times per minute. On the first day I reeled for twenty minutes, which gave two hundred and sixty-six and two thirds yards; on the third day, the second being Sunday, for twenty-five minutes, giving three hundred and thirty-three and one third yards; and on the fourth day, for eighteen minutes, giving two hundred and thirty-three and one third yards,—amounting in all to eight hundred and thirty-three and one third yards in three or four days. This was all that could be got, and the spider herself seemed unable to evolve any more; but on killing her and opening her abdomen, plenty of the gum was found in the little silk bags into which it is secreted. As this has always been the case, I have concluded that the evolution of the silk is almost entirely a mechanical process, which is but little controlled by the spinners themselves, and that the gum requires some degree of preparation after it is secreted before it is fit for use as silk; for it must be remembered that with the spider, as with the silk-worm, the silk is formed and contained in little bags or glands in the abdomen, not as threads, but as a very viscid gum. This passes in little tubes or ducts to the spinners, through minute openings, in which it is drawn out into filaments,