300 SEA-SIDE STUDIES. 



the sun, a young one will sprout from tlie injured 

 parts/' Here Harvey's dictum receives direct contra- 

 diction : the Polype which is produced from a wound 

 in the body of the parent, being in every respect simi- 

 lar to the Polype which is produced from an egg. 



It was in 1744 that Trembley made known to the 

 world the astonishing reproductive powers of the 

 Hydra.* The following year*]- Bonnet published his 

 not less astonishing revelations on the reproduction of 

 Aphides, or plant-lice. The Aphis, a winged insect 

 familiar to most readers, deposits its eggs in the axils 

 of the leaves of plants at the close of summer, and 

 these eggs are hatched in the following spring ; but 

 the insect which issues from the egg is a Avingless, 

 sexless insect. It was known that this wingless insect 

 brought forth its young alive. Bonnet proved that 

 this took place when no male insect was present — in 

 fact, he proved that the insect was a virgin mother, 

 and astoundingly fertile. He isolated the young 

 Aphis as soon as it was hatched, reared it in strict 

 seclusion, and watched it daily, almost hourly, with 

 the patient tenacity of a naturalist of genius. He has 

 left on record his anxieties, his tremulous agitation 

 lest its death should supervene to frustrate his la- 

 bours ; and his joy, after seeing the captive four times 

 change its skin and reach its normal development, to 

 observe that this absolute virginity did not in the least 



* Trembley : Memoires sur un genre de Polypes d'eav, douce, 4to, 

 Leyden, 1744. 



-f- Bonnet : Traite dJInsectologie, 2 vols., 1745 ; vol. i., p. 26 et seq. 

 A better edition is that printed at Amsterdam, 1780. 



