SILK-PRODUCING INSECTS. 29 



an intense degree of cold, produced by an artificial 

 freezing mixture, in which they remained for five 

 hours without being frozen, the thermometer of 

 Fahrenheit having fallen to 56 below zero, although 

 the liquid portions of an insect's egg has been shown 

 by John Hunter to freeze at 15 Fahr. The eggs 

 submitted by Spallanzani to this treatment were 

 afterwards hatched. 



In 1854 the Governor of Malta made several 

 reports upon the Bombyx Cynthia for the informa- 

 tion of the Society of Arts. It had been intro- 

 duced into Malta from India that year, and appeared 

 hardy and wonderfully prolific. Yet it failed in 

 1855. The author of these observations had, how- 

 ever, previously distributed its eggs throughout 

 Italy, France, and Algeria, and, continuing to watch 

 the trials made in these countries, he found that 

 the new silkworm had nourished and had been 

 carried into Spain and Portugal. He therefore 

 reintroduced it into Malta. At the end of July 

 1857, he received a few eggs by post in a quill 

 from Paris, and these have multiplied in an extra- 

 ordinary manner. The winter season (December) 

 appeared to affect the caterpillars even in Malta 

 they grew slower than in summer, but nevertheless 

 appeared healthy. 



In France experiments are being made on the 

 silk of the B. Cynthia, which is found to be very 



