174 APPENDIX TO MEMOIR OF PELTIER. 



bled, it lias lost tbcm all ; it is then no more than a very thin and diaphanous 

 membrane in which no organ is any longer perceptible. In this state, all move- 

 ment has ceased ; the particles of the membrane itself become disintegrated 

 and the vorticella dissolves globnle by globnle ; at other times a rupture takes 

 place in a part of the membrane, the internal liquid escapes, and the animal 

 lias ceased to live. 



ricpwduction of infusoria. — It is known that among the infusoria, properly 

 so called, reproduction takes place commonly by fissiparity ; they continue sep- 

 arating into two parts, and thus form new beings. This mode of reproduction 

 is so rapid that a single paramecia oT)served for some days divided itself four 

 times in 24 or 30 hours, producing thousands of new creatures in the lapse of a 

 few days. This generation only proceeds with activity when an exuberant 

 noimshment is sup})lied to these animals. Peltier, however, produced l)y inani- 

 tion, in a great nmnber of animalcules, an efiect analogous to that which results 

 from an excess of mitrition. 



There are species wlrich possess a contractile dorsal vessel, in which w'e can 

 follow the progress of the nutritive liquid ; such are the digitated naiadtB. If 

 these animals be subjected to inanition, Ave shall see, in proportion as the liquid 

 is impoverished, a contraction of the dorsal vessel, which is less stretched oitt, 

 and stops Avhere the liquid ceases to arrive, because it has been absorbed by the 

 anterior parts. When this movement is thus arrested, there will be seen to be 

 formed, at the middle of the body, at the point Avhere the nutritive liquid ceases 

 to arriA'e, and Avhere the contraction of the vessel stops, two large absorbent 

 vesicles, which imbibe for the behoof of the posterior part. As soon as these 

 A^esicles enter into action the second half of the dorsal vessel resumes its contractile 

 movements ; these contractions, be it understood, take their origin in the ncAV 

 A'esicles, and have no communication Avith the anterior part nor any synchro- 

 nism Avith its movement. In front of these \-esicles, a constriction is presently 

 formed, which increases by degrees, and Avhicli ends by completely separating 

 the two portions, Avhich then constitute tAvo distinct individuals. 



The anterior portion, better organized and better supplied Avith ai)pendages 

 for alimentation, has more vivacity, more energy, than the other. If Ave suc- 

 ceed in preserving the drop of Avater seven or eight days, the nutritive matter 

 diminishing more and more, there occurs for the tAvo halves that Avhich occurred 

 for the entire animal : the quantity' absorbed by the anterior parts is no longer 

 sufficient for the total alimentation, and the posterior part is left in a state of 

 complete inanition. It Avas thus that Peltier obtained in one instance a neAV 

 separation into tAvo of each of the two former halves, and e\^entually a new 

 separation of the tAVO quarters proceeding from the anterior half ; the two sep- 

 arated parts of the posterior half had ceased to live before he could effect a 

 ncAV separation. The result, therefore, Avas the formation of six individuals 

 proceeding from the separation of the parts Avliich the dorsal vessel could no 

 longer supply with nourishment. 



Peltier has verified the same fact Avith regard to the pustulous kerones ; hav- 

 ing subjected these animals to protracted inanition, ho perceiA'cd that, in the 

 middle of the l)ody, an indentment was formed Avhich Avcnt on constantl}' 

 increasing, and finally separated the animal into two parts ; the anterior half 

 continued to live, it appeared even to acquire new energy by the loss of the 

 posterior half of its substance, Avhile this latter often died at once, though some- 

 times it remained alive for a certain interval. In every case, the instant of the 

 death of the individual restored to liberty and their own spontaneity the rest 

 of the globules Avhich happened to be in its interior. Peltier observed also 

 similar peculiarities in the kidney-shaped cyclidse. 



M. Dujardin had inferred from his researches that certain animals might be 

 produced by means of lobes of their substance abandoned by them on the 

 bodies to Avhich they attach themselves. Peltier has confirmed this idea by 



