44 ON MULBERRY TREES AND SILK. 



days before they were exposed to hatch, they were 

 placed in a cellar, in a temperature of about 55, 

 where they began, the third day, to hatch, and the 

 next morning came out in great numbers on the ta- 

 ble, in a room where the temperature was 82, that 

 of the common atmosphere at the time. 



I mention these particulars, as great disasters have 

 befallen the late broods of silkworms, in every por- 

 tion of the Union, the present season, owing un- 

 doubtedly to the erroneous management of the eggs, 

 particularly, in improperly retarding them for suc- 

 cessive hatchings. These disasters seemed for a 

 while to threaten to blast the prospects of the great 

 cause of silk growing in the United States. But a 

 remedy proposes itself in what is termed the " new 

 theory," which supposes that the eggs cannot be 

 retarded a length of time beyond the natural season 

 for hatching, or forced to premature hatching, with- 

 out doing violence to the nature of this insect. The 

 supposition is, that the silkworm, like many others, 

 is an annual insect, taking just one year to complete 

 the circle of all its changes and of its existence. All 

 my experiments tend to aid in demonstrating the 

 truth of this position. The parent worms from 

 which my present stock was produced, hatched 

 spontaneously in a common cellar, just about the 

 completion of a year from the production of their pa- 

 rent worms. These worms were unusually healthy, 

 only twenty out of ten thousand failing to produce 

 each a cocoon, only 226 of which were required to 

 make a pound. But their progeny, which I have fed 

 the present season, it will be perceived, were re- 

 tarded forty-five days from hatching, beyond the pro- 

 per time, according to our new theory. These 

 worms were apparently unhealthy, which could be 

 perceived on their first hatching. They appeared 

 dilatory, some died in infancy, and some survived to 

 the fifth age and then died. Many at that time 

 manifested a sluggishness, and although many good 



