176 



II. When we have once conceived that all the exte- 

 rior parts of the same kind are jointed into each other, 

 or laid one on another, the production of new organs 

 has nothing embarrassing in it ; and with regard to this, 

 there is not any essential difference betwixt the five 

 jfnoultings that^ precede the transformation : nothing 

 more is requisite in all that but a simple developement. 



But it is not absolutely the same, with respect to 

 changes that happen in the viscera before, during, and 

 after the metamorphosis. Here the light that should 

 guide us is almost extinguished, and we are constrained 

 to grope in the dark. 



It does not appear that the insect changes its viscera 

 as it does its skin. Those which existed in the cater- 

 pillar, exist likewise in the chrysalis : but they are mo- 

 dified, and it is the nature of these modifications, and 

 the manner by which they are performed, which elude 

 our researches. 



A little before the metamorphosis, the caterpillar re- 

 jects the membrane that lines the inside of the intesti- 

 nal bag. This bowel, which has hitherto digested gross 

 food, must hereafter digest that which is extremely de- 

 licate : the blood that circulates in the caterpillar, from 

 the hind part towards the head, circulates a contrary 

 way after transformation. If this inversion be as real 

 as observations indicate, what idea does it not give us 

 of the changes the inside of the animal experiences] 

 Those, which the circulation of the blood in a new-born 

 infant undergoes, are in a manner nothing in comparison 

 of them. 



12. Whilst nature is labouring to change the viscera, 

 and to give them a new life, she is employed, at the 

 same time, in the developement of divers organs, which 

 were useless to the insect while it lived under the form 

 of a caterpillar, and which the new state whereunto it is 

 called renders necessary for it. The better to insure 

 the success of her different operations, she causes the 

 insect to fall into a deep sleep, during which she carries 

 on her work at leisure, and by insensible degrees, 



