[ 175 ] 62 



The following are the signs of the speedy vivification of the silk- 

 worm : 



The ash-gray color of the eggs grows bluish, then purplish; it theu 

 again grows gray, with a cast of yellow; and finally, of a dingy white. 



If the eggs of silkworms belonging to different persons, are put into 

 the same stove-room, great differences will be observable, not only int. 

 changes of color in the eggs, but also as to the period of hatching the 

 worms. The insects of the eggs that have been preserved through 

 the winter in an even and gentle temperature, and those of the eggs 

 which have undergone maceration,* come forth in four or five days 

 sooner, namely, at the 71st, 73d, or 75th, degree of temperature; 

 whilst those that have been kept in a very cold atmosphere, appear 

 some days later. 



This stove imparts to each egg the degree of heat necessary to 

 change the embryo it contains into the worm. When the eggs have 

 been kept in a certain degree of warmth, it requires less stove-heat 

 to develope the silkworm. This is so true, and so worthy of notice, 

 that we find, if, in the winter, the eggs have been kept in an atmo- 

 sphere of .55°or59°, or heaped together, they spontaneously come forth, 

 or without the aid of the stove, when the room is but slightly warmed, 

 and before the mulberry tree has given any sign of vegetation. In 

 this case, these worms must be thrown away, unless other food is at 

 hand upon wliich they can be sustained for a time. This circum- 

 stance is, therefore, of essential consequence, and should be noted to 

 prevent its occurrence. A little delay in the hatching of the worms 

 is no loss; whereas it may be a very serious loss, if we anticipate, by 

 a few days, the proper period of hatching. To backen them, when 

 very near the time of coming forth, by altering the temperature, in- 

 jures them materially. To prevent the loss of worms thus permitted 

 to hatch too early, they may be fed on lettuce, upon which it is well 

 ascertained that they can be well sustained in their early stage. The 

 experiments of General Mordaunt, in England, were referred to long 

 since.t Miss Rhodes fed them, upon two occasions, successfully, 

 with this food. She gave it to the first parcel for the first week, and 

 then substituted mulberry leaves. Upon a second occasion, the worms 

 came out on the first of June, and were kept on lettuce until the 24th 

 of the month. Mulberry leaves were then given; in less than a week 

 after the change of food, they began to spin, and the cocoons were as 

 fine and as firm as any she ever had. She did not lose a dozen worms 

 of many thousands.! Her experience has recently been confirmed by 



^ Bv maceration is commonK' understood eg-gs preserved in bags, under cushions 

 or mattresses, or in blankets, and similar thing's, until the moment of putting them in 

 the stove-house. 



This uncertain method must be injurious to the regular and secure developement 

 of the womis. It oitcn happens tliat great quantities are spoiled by maceration, the 

 worms coming forth, and shortly dying. 



It appears rational that, when there is a certain and regular method, we should 

 not adopt anotlier, the result of which is imcertain and irregular, particularly when 

 this sccm-e method is not attended by any great expense. 



■j- Bee, by Dr. Anderson. Edinburgh, vol. 8. p. 262. 



:;. Trans. Soc- Arts, Lond- vol. 4, p. 149. 



