452 HABITATIONS OF INSECTS. 



knew that except by rare accident no other animals are 

 to be found in galls, besides grubs of different kinds 

 which they rationally conceived to spring from eggs, 

 were chiefly at a loss to account for the conveyance of 

 these eggs into the middle of a substance in which they 

 could find no external orifice. They therefore inferred 

 that they were the eggs of insects deposited in the 

 earth, which had been drawn up by the roots of trees 

 along with the sap, and after passing through differ- 

 ent vessels had stopped, some in the leaves, others in 

 the twigs, and had there hatched and produced galls ! 

 Redi's solution of the difiiculty was even more extra- 

 ordinary. This philosopher, who had so triumphantly 

 combated the absurdities of spontaneous generation, 

 fell himself into greater. Not having been able to 

 witness the deposition of eggs by the parent flies in 

 the plants that produce galls, he took it for granted 

 that the grubs v.^^hich he found within them could not 

 spring from eggs : and he was equally unwilling to 

 admit their origin from spontaneous generation, — an 

 admission which would have been fatal to his own 

 most brilliant discoveries. He therefore cut the knot, 

 by supposing that to the same vegetative soul by which 

 fruits and plants are produced, is committed the charge 

 of creating the larvae found in galls'^! An instance 

 truly humiliating, how little we can infer from a man's 

 just ideas on one point, that he will not be guilty of 

 the most pitiable absurdity on another ! 



Though by far the greater part of the vegetable ex- 

 crescencies termed galls, are caused by insects of the 

 genus Cj/n/j>s, they do not always originate from this 



* Dt Iiiicctis, 233 &c. 



