ANNELIDA. 



buried itself in the mud, and no doubt there completed its de- 

 velopement. 



(254,) It is very generally believed, that even the earthworm may 

 be multiplied by mechanical sections, the separated portions repro- 

 ducing such parts as are removed in the experiment, and again 

 becoming perfect. Careful experiments made to ascertain how far the 

 statements of former authors upon this subject are substantiated, 

 prove that the assertion is not entirely without foundation, al- 

 though by no means to the extent indicated in their writings. It 

 would indeed be easily credited that the removal of the hinder 

 part of the body of an earthworm would not necessarily destroy the 

 anterior portion, since no organs absolutely essential to existence 

 are removed by the operation, and even the course of the circu- 

 lating fluids would not be materially interrupted by the mutilation ; 

 but that the hinder moiety should be able to reproduce the mouth, 

 gizzard, and stomach, the complicated apparatus of moniliform 

 vessels and the sexual organs, contained in the anterior segments, 

 could scarcely be deemed possible, and the assertion has been 

 satisfactorily disproved by actual observation. On cutting an 

 earthworm in two, the anterior portion is found in fact generally 

 to survive ; and the wound caused by the operation, becoming 

 gradually constricted, is soon converted into an anal orifice, render- 

 ing the animal again complete in all parts necessary for its ex- 

 istence. This, however, is by no means the case with the posterior 

 portion ; for although it will exhibit, for a very long period, indica- 

 tions of vitality, no signs of reproduction have been witnessed, and 

 it invariably perishes. 



(255.) Nevertheless, although it is thus proved that the earthworm 

 cannot be multiplied by mechanical division, it is undeniably able 

 to reproduce small portions of its body, the removal of which does 

 not implicate organs essential to life. In the experiments of 

 M. Duges,* for example, it was found that four, or even eight, of 

 the anterior rings might be cut off with impunity, although the 

 cephalic pair of ganglia, the mouth, and a part of the oesophagus 

 were necessarily taken away. In worms thus mutilated, after the 

 lapse of from ten to thirty days, a conical vascular protuberance 

 was observed to sprout from the bottom of the wound ; and, in 

 eight or ten days later, this new part had become so far developed, 

 that not only all the lost rings were apparent, but even the upper 

 lip and mouth had assumed their normal form, and the animal 

 again began to eat and bury itself "in the earth. 



* Loc. cit. p 2 



