COMMERCIAL VALUE OF SPIDER SILK. 89 



Stillbers has made cloth of spider's silk which has been employed for 

 purposes of surgery. He only uses tropical spiders, from which, thanks to 



a scientific culture, lie has obtained a much greater return than 

 An Eng- ^^.,^g foreseen by Reaumur. The spiders which he uses are large 

 Aff t species from America and Africa. They are placed in octagonal 



cases, where a sufficiency of insects is served to them every day. 

 In the room where the cases are kept a constant temperature of 60° Fahren- 

 heit is maintained, and a liquid composed of chloroform, ether, and fusel 

 oil is allowed slowly to evaporate. That is to say, spiders spin best when 

 they are under the influence of an antesthetic, as Professor Wilder liad 

 suggested, the reason for which has heretofore been alluded to. 



Mr. Stillbers is said to keep five thousand of these cases in a room forty 

 yards long by twenty wide and five high. The spiders lay eggs of various 

 colors, enclosed as usual with cocoons. These are gathered up and [ire- 

 pared by the same mechanical and chemical operations as tlie cocoons of 

 the Bondjyx moth. One cocoon yields one hundred and twenty to one 

 liundred and fifty yards of thread by a process which is kejit absolutely 

 secret. The stuff obtained has a texture resembling ordinary silk, but 

 tliick, stiff, and a dirty color. It is all the more necessary to bleach it, 

 because the color is by no means uniform. It is bleached by treatment 

 with oxygenized water. Then it is tanned and softened, when it assumes 

 a pretty yellow tint, and becomes brilliant and smooth. 



To make a thread say a mile in length requires between forty and fifty 

 cocoons. This is a great advance on Reaumur's calculations, but still 

 falls far short of a practical indu.strial success. The stuff obtained must 

 be sold at a very high price in order to obtain the merest compensation 

 for all this trouble and expense. Thus, the last attempt at economizing 

 the silk product of spiders returns to the method of Bon, to utilize the 

 cocoon, and abandons the reeling process of Termeyer and Wilder. 



