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152 CULTIVATION AND MANUFACTURE OF SILK.
and as one end is always attached to the spinnerets, he must
mean that the double of the thread flies ofi". In his previous
publications, however, Latreille had contented himself with
copying the statement of Dr. Lister. " In order to ascertain
the fact," says Mr. Rennie, " and put an end to all doubts, we
watched, with great care and minuteness, the proceedings of
the long-bodied spider above mentioned, by producing a stream
of air in the same manner, as it perambulated the brim of the
glass. It immediately, as the other had done, attached a thread
and raised its body perpendicularly, like a tumbler standing on
his hands with his head downwards ;
but we looked in vain for
this thread bending, as we had at first supposed, and going off
double. Instead of this it remained tight, while another thread,
or what appeared to be so, streamed off from the spinners, simi-
lar to smoke issuing through a pin-hole, sometimes in a line,
and sometimes at a considerable angle, with the first, according
to the current of the air,—the first thread, extended from the
glass to the spinnerets, remaining all the while tight drawn in
a right line. It further appeared to us, that the first thread
proceeded from the pair of spinnerets nearest the head, while
the floating thread came from the outer pair,—though it is
possible in such minute objects we may have been deceived.
That the first was continuous with the second, without any
perceptible joining, we ascertained in numerous instances, by
catching the floating line and pulling it tight, in which case
the spider glides along without attaching another line to the
glass ; but if she have to coil up the floating line to lighten it,
as usually happens, she gathers it into a packet and glues the
two ends tight together. Her body, while the floating line
streamed out, remained quite motionless, but we distinctly
saw the spinnerets not only projected, as is always done when
a spider spins, but moved in the same way as an infant moves
its lips when sucking. We cannot doubt, therefore, that this
motion is intended to emit (if eject or project be deemed words
too strong), the liquid material of the thread ;
at the same time,
d'air pousse I'autre extr^mitd de I'un d'eux au de li de I'obstacle."—Diet. Clas-
sique d'Hist. Nat., vol. i. p. 510.