360 ARACHNIDA—-ARANEAE CHAP. 
of the House-spider, taken internally, was considered a specific 
for the ague, though its value as a styptic has been recognised 
in quite recent times. It is, however, with other uses of Spider 
suk that we are here concerned. 
Spider silk has been extensively used in the micrometer eye- 
pieces of telescopes where very fine intersecting lines are required. 
For this purpose the radial or scaffolding lines of the circular 
snare were selected, the spiral being unsuited on account of its 
row of viscid beads. Professor C. V. Boys has, however, dis- 
covered in his quartz fibres a material better adapted for this 
purpose. 
Several attempts have been made to weave the silk of Spiders 
as a substitute for that of the silk-worm. Web silk is, of course, 
far too fine to furnish a durable material, but the cocoons are 
usually formed of coarser silk, and it is with them that the 
experiment has been tried. About the beginning of the eighteenth 
century certain stockings and mittens made of Spider silk from 
the cocoons of Hpeira diademata, by M. Bon of Languedoe, 
attracted so much attention that the Academy desired M. Réaumur 
to investigate the matter. His report was unfavourable to the 
commercial utility of Spider silk. The cocoon threads, though 
“eighteen times stronger than those of the web, were but one-fifth 
of the strength of those obtained from the silk-worm, and the 
lustre was inferior. A still more fatal objection, however, was 
founded upon the cannibalistic habits of the spider, and the 
difficulty of furnishing it with acceptable food. 
M. Vinson has recorded that some of the spiders of Madagascar, 
especially Hpeira madagascarensis, are far better adapted than 
any of our Enelish species to a commercial use. They furnish 
silk of a beautiful clear yellow colour; they are accustomed 
to live harmoniously together in families; and the range of 
climate in which they can thrive is very considerable. The 
Creole ladies of this island, under the administration of General 
Decaen, wove a magnificent pair of gloves from spider silk, with 
their own hands, for presentation to the French Empress. 
Poison of Spiders.— All spiders possess poison-glands, 
which have their openings on the fangs of the chelicerae. The 
action of the chelicera in striking does not express the venom, 
but the poison-bag itself is covered with a muscular coat by 
which the contained fluid is expelled. It is highly probable, 
