APPENDIX. 319 



worms into halves, — into three, four, and, ultimately, into as many 

 as fourteen j)ieces ; and as the entire animal did not much exceed an 

 inch in length, the portions must, in many of the experiments, have 

 been necessarily very small. The halves became vs^hole worms, — the 

 thirds and quarters also, — and the morsels grew to be complete indi- 

 viduals, not to be distinguishable from the original stock. Occasion- 

 ally, when the divisions were carried to a high number, as to fourteen, 

 some of the sections perished, but there was no one in particular 

 more subject to this misfortune than another. The head produced 

 a body and tail ; the posterior half a head with all its organs ; and 

 of .the intermediate portions it was observed, as a uniform law, that 

 the head always pullulated from the front section, and the tail always 

 from the hinder*. And it was also noticed, that after a section, the 

 front of a hinder portion became immediately endowed with the 

 office and functions of a head, — viz. it was pushed forwards in pro- 

 gression, it examined the way, and it was used to burrow in the soft 

 soil. The redintegration began within a few hours after the ampu- 

 tation was made in warm weather, but, in colder weather, several 

 days might elapse ; and the completion of the process was a good 

 deal dependent on the temperature. The new parts could readily 

 be distinguished for some time from the old by their paler colour 

 and lesser diameter ; but ultimately they became like to the original, 

 and were endowed with the same vital powers. These new portions, 

 if they were cut away, were reproduced again and again, — as often 

 at least as the patience of the experimenter could induce him to 

 carry on his observations. With the worms that are more strictly 

 terrestrial, experiments of this kind were found not to be so uniformly 

 successful. The renewal of the amputated parts was comparatively 

 slow ; and very often the worm, and the severed pieces, died under 

 the injuries and treatment inflicted upon themf . 



These experiments of Bonnet were successfully repeated by M. 

 Lyonet in 1741, on a kind of aquatic worm about 3^ inches in 

 length, and as thick as the string of a violin. From its size, he was 

 enabled to cut the worm into not less than thirty or forty fragments ; 

 and yet each lived, and became, in due season, like unto the parent. 

 Father Mazolleni of Rome, having these facts communicated to him 

 by M. de Reaumur, hastened to confirm them by his own experience, 

 although he seems not to have carried the sections of the body to 

 the number which Lyonet had done. 



From the experiments he had himself made, and from those of 

 his friends just mentioned, Reaumur concluded that if there were 

 any species of these aquatic worms which did not possess the pro- 

 perty of reproducing amputated parts, they were exceptions to the 

 rule of life by which the growth of these animals was governed. He 



* "The middle part of an earthworm, deprived of hoth ends, expeditiously 

 moved away when touched." — SpallanzanV s Tracts^ i. p. xlvi. See Williams, Rep. 

 1851, p. 250. 



t Traite d'Insectologie ; ou, Observations sur quelques especes de Vers d'eau 

 douce, qui, coupes par morceaux, deviennent autant d'Aniraaux complets. Par 

 M. Charles Bonnet. 2de partie. Paris, 1745, 12mo. 



