d 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, uniting and drying instantly in the air, and so
forming the single fibre from each spinner.

The silk obtained the first day was of a deep yellow; to my great
astonishment, the second reeling from the same spider gave silk of a
brilliant silver-white color; while on the third occasion, as if by
magic, the color had changed again, and I got only _yellow_ silk. The
hypothesis of individual peculiarity, adopted the previous year to
explain why some spiders gave yellow, and others white silk, was now
untenable; and, remembering that, beside these two positive colors there
was also (and indeed more commonly) a _light yellow_, as if a
combination of the other two, I saw that the real solution of the
mystery must lie in the spinners themselves. Examining carefully the
thread as it came from the body, it was seen to be composed of two
distinct portions, differing materially in their size, their color,
their elasticity, and their relative position; for one of them was
_white_ and _inelastic_, crinkling and flying up when relaxed, and
seemed to proceed from the _posterior_ of the two principal pairs of
spinners, while the other was _larger_, _yellow_, so _elastic_ that when
relaxed it kept its direction, and seemed to come from the _anterior_
pair of spinners, and so, in the inverted position of t