290 



THE BEGINNINGS OF IIFE. 



met 



even towards 



been derived from the multiplication of a few solitary 

 individuals, even by the combined methods of fission 

 budding, and the so-called sexual reproduction. 



It is often stated that Ciliated Infusoria multiply 

 very rapidly by means of fission. But 

 the close of the last century Gleichen^ declared that 

 during the fifteen years in which he had been continually 

 watching these animals, he had only observed a process 

 of fission occur three times; and it was only after 

 some years of observation that De Blainville2 

 actually able to satisfy himself that such a mode of 



He subsequently saw it 

 occur occasionally in certain specimens belonging to 

 the genus Kolpoda. Of late years, also, similar testi- 

 mony has been given on this subject. Mantegazza de- 

 clares that he has only seen ciliated Infusoria undergo 

 such a process of division two or three times, though 

 millions of these animals of difFerent species had passed 



was 



division might take place. 



under his observation 

 months ; while M 



during 



a space of fourteen 



ing over many years, says he has never once seen a 

 Paramecium divide. Specimens of Kolpoda he has how- 

 ever more frequently found presenting appearances sug- 

 gestive of fission. But with regard to the VortkelU, 

 which, since the times of Spallanzani, have been de- 

 scribed as particularly prone to undergo such a division, 



4 



r 



■^ 'Dissert, sur la Generation, &c/ ■ 

 2 'Diet, des Sc. Nat.' torn. Ix. p. t^^4. 



the fac 



(Oil, 1^ 



ttld be wel 

 otier obser 

 ^- ' On thi 

 it te watche( 



wim. 



\ 



y rather in ai 



\ 



I lie has ■m 

 four or li 



in 



rep.y 



'to several tir 

 ■IS belo 

 to these 



It! 



* « 



time 



of 



f( 



occup 



oiind 



that 



. ''\ 



Pt. Rer4 . , 



^•of 



\ 



