Leaders. 91 



out affecting the quality of the silk. " The silk in the 

 reservoirs is sometimes used in commerce, being sold 

 under the name of gut. The process of obtaining the 

 gut is very simple ; it consists in preparing worms ready 

 to spin by putting them in strong vinegar for eighteen 

 hours ; a transverse opening is then carefully made on 

 the under-side and about the middle of the body, taking 

 care not to injure the silk reservoirs, which are very dis- 

 tinct. The glands or reservoirs are then taken out and 

 stretched parallel to each other on a board, and dried 

 in the shade for several days." It will yield gut twenty- 

 five inches long. 



The Saturnia cynthia, or, as it is sometimes called, 

 the Samia cynthia, though a native of Japan, has be- 

 come acclimated, and is sometimes found wild in this 

 country on the ailanthus-tree. This is its favorite food, 

 hence it is sometimes called the ailanthus silk- worm. An 

 excellent paper on its natural history and cultivation, by 

 W. V. Andrews, may be found on page 311, vol. ii., of 

 the American Naturalist. A colored illustration of both 

 worm and moth maybe found on page 149, vol. xxxii., of 

 the Naturalises Library, heretofore alluded to. From 

 its silk is made a " seemingly loose texture, but of in- 

 credible durability, the life of one person being seldom 

 sufficient to wear out a garment made of it." 



We all know how prolific and how rapid is the growth 

 of the ailanthus, springing from a stub to considerable 

 height in a single season, and this on the poorest soils. 

 This worm is not a wanderer, but remains on the tree 

 on which it is placed as long as its food lasts. It is ex- 

 tremely hardy. Two broods a year may be raised. I 

 am not informed as to the length of gut which may be 

 drawn from it, but its greatly superior size indicates that 



