I. AGRICULTURE AND RURAL ECONOMY. 379 



fied when once began without clanger, but the first, lasting 

 5 or 6 months, is more manageable, and the period can be re- 

 duced to 20 days or extended to 18 months at will. To pre- 

 vent an egg from developing at the ordinary period, it is nec- 

 essary to keep it, from the moment of laying, at a tempera- 

 ture between 59 and 68 Fahrenheit, and to expose it to cold 

 during a period of 15 days, at least 3 months before the ap- 

 pointed time for hatching. On the other hand, to cause the 

 egg to hatch before the ordinary time, it is necessary to ex- 

 pose it to cold 20 days after laying, and to leave it at that 

 temperature for 2 months, and then to remove it. Six weeks 

 after it will be found to be in the same condition as the nor- 

 mal eggs, and may be treated in the same manner. In this 

 way it is possible to have the eggs ready to hatch out at any 

 time of the year. 3 B, xxvi., October 26, 1871, 266. 



DELPRINO's MODE OF TREATING SILK-WORMS. 



The attention of visitors to the Italian section of the French 

 Exposition of 1867 was attracted to certain small w r ooden 

 pigeon-holes, each of which contained a silk-worm, where it 

 was occupied in constructing its cocoon without disturbance 

 from its neighbors. This w T as an invention of Dr. Delprino, 

 of Yesime, in Piedmont, and which, although very simple in 

 itself, formed an important innovation in the art of raising 

 silk-worms. Since that time this and other peculiar inven- 

 tions of the same gentleman have been widely adopted, and 

 have done much toward protecting the silk interest from the 

 losses which the recent multiplication of diseases and other 

 casualties have brought about. 



The difficulty in the ordinary magnaneries, or worm-houses, 

 is that the worms are mixed together, the strong oppressing 

 the weak, and also heaped upon each other in a mass, as to 

 produce greater or less injury. In Delprino's system a life 

 in common is interdicted as much as possible, although during 

 the feeding of the worms it is impossible to isolate them en- 

 tirely. During that period they are kept together, but al- 

 lowed ample room for moving about, being placed on small 

 movable hurdles which can easily be changed. This produces 

 constant ventilation, and prevents the danger of a great ag- 

 glomeration, in consequence of which the transformations 

 marking the different ao;es. involve much less loss. When 



