132 THE SILK WORM MOTH. 



degree in which their bulk and length are increased, 

 and the very limited time in which that is accomplished. 

 Count Dandolo counted and weighed many hundred 

 thousand eggs, and found that, on an average, sixty- 

 eight sound Silk Worm's eggs weighed one grain. 

 One ounce,* therefore, comprised 39,168 eggs. But 

 one-twelfth part of this weight evaporates previous 

 to hatching, and the skins in which they are con- 

 tained are equal to one-fifth more. If, therefore, 

 from one ounce, composed of 576 grains, 48 grains 

 be deducted for evaporation, and 115 for the shells, 

 413 grains will remain, equal to the weight of 39,168 

 young worms ; and according to this computation, 

 54,526 of the larvae, when newly hatched, are 

 required to make up an ounce. After they part with 

 their first skin, 3840 worms are found to be this 

 weight, so that the bulk and weight of the insects 

 have, in a few days, been multiplied more than 

 fourteen times. After the second change, 610 larvae 

 weigh an ounce, the weight of the animals being 

 increased, in the intermediate time, six fold. In the 

 week passed between the second and third ages, the 

 number of worms required to make up the weight 

 decreases from 610 to 144, their weight being, there- 

 fore, more than quadrupled. During the fourth age, 

 a similar rate of increase is maintained ; thirty-five 



* This ounce contains 576 grains ; 8.5325 of these grains 

 equal seven grains troy. One ounce avoirdupois is therefore 

 equal to about 533 of these grains, and between one-twelfth 

 and one-thirteenth ounce avoirdupois equals one of the above 



