( 6o ) 



off, either near tlie organ from whence tlie threads proceed, (marked 

 \u/g. 30, with the letter C) or clfe witliin the body of the Silk-worm 

 itfelf. And on thefe occafions I alfo obferved that the threads were 

 covered with much more of the vifcous or gummy fubltance than 

 ullially adheres to them when fpim by th(i ^^orm, '\\hicii iubftance 

 alio appeared of a yellow colour. 



P\u-ther, I took a Silk-worm which had fpun more of its ball or 

 cone tlian any I had before examined, and on opening it, I perceived 

 that the part which mfig. 30, had appeared of a red colour was now 

 quite yellow ; and wlien I opened another Silk-worm which had, as it 

 were, confumed or exhaufted all its filk in fpinning the web, the fame 

 parts appeared quite of a pale colour. 



V\henl examined by the microfcope that part which is rcprefented 

 in fig. 31, at LMN, I difcoveredin it a great number of blood vellels, 

 moftly compofed of annular parts or rings. A fmall portion of one 

 of thefe veflels in a place where it divides into two branches, is rc- 

 prefented at^^. 32, FGH I K. This was not one of the largeft vellels 

 I faw, for near to it was one four times the fize. 



1 have at feveral times when the Silk-worms had, as I fu])pofed, 

 )iearly finidied their web or covering, cut it open, in order to obferve 

 the change they underwent, and at that time I remarked, that when 

 the ikin about the head became loofened, the worm w as then changed 

 into a chryfalis or aurelia, and nothing wanting to compleat that 

 change, but the putting off' its (kin of a worm. But when I myfelf 

 endeavoured to ftrip off" this fl<.in, I found the under one fo foft and 

 tender, that I could not avoid injuring it. 



Moreover, I have examined by the microfcope the Silk- worm, 

 when it firft iffiied from the egg, to difcover, if pollible, whether the 

 exceeding flender thread Ipun by fo minute a creature was a 

 double thread, and in more than one inftance, I found tiiis to be the 

 cafe. Thefe threads I judged to be above a thoufand times flenderer 

 than thofe I'pun by full grown Silk-worms, and tliey were all covered 



