THE BEGINNINGS OF LIFE. 473 



smaller portions (Fig. 84, ,/), and after having attained 

 a length of T ^sV' they become almost motionless, lose 

 their flagellum, and then develop either into small 

 forms of Ciliated Infusoria, or else become converted 

 into active Amoebae (k, /, m). The latter, after increasing 

 much in size, may as Dr. Braxton Hicks l and Prof. 

 Schaaffhausen 2 stated several years ago, and as Dr. 

 Gros had long previously announced ultimately be- 

 come transformed, with or without previous encystment, 

 into some larger forms of some of the Ciliated Infusoria 3 . 

 Evidence of the most varied nature, indeed, as well 

 as the independent testimony of many successive 

 observers, all concur in pointing to the conclusion that 

 the precise form of life produced in cases of hetero- 

 genetic transformation is to a very great extent de- 

 pendent upon the size or mass of the matrix which 

 undergoes transformative changes. This notion is 

 impressed upon us by Dr. Gros in almost every page of 

 his memoir; it was the view independently adopted by 

 Mr. Carter 4 ; and again, later still, in 1 859, it was the 

 doctrine announced by M. Nicolet based upon obser- 



1 See p. 378. 2 Cosmos, t. xxii. p. 635. 



3 Mr. Metcalfe Johnson frequently speaks of the development of Para- 

 mecium and Kolpoda from Monad forms (see ' Month. Microsc. Journ.,' 

 Aug. 1869, Jan. 1870, and Nov. 1871, PI. CIII. fig. vii.) ; whilst Prof. 

 A. M. Edwards of New York has recently watched the conversion of 

 Amoebae into Ciliated Infusoria of the same kind (' Proceed, of Lyceum 

 of Nat. Hist.' 1871, p. 216). 



4 ' Ann. of Nat. Hist./ vol. xvi. Although subsequently, as we have 

 already pointed out, Mr. Carter gave a different interpretation to the 

 facts (see p. 391). 



