THE BEGINNINGS OF LIFE. 473 



smaller portions (Fig. 84, h^j)^ and after having attained 

 a length of x 2V0'' '^^'^^y become almost motionless, lose 

 their flagellum, and then develop either into small 

 forms of Ciliated Infusoria, or else become converted 

 into active Amoeb-x {k^ /, m). The latter, after increasing 

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

 Schaaff hausen 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^. 

 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'^; and again, later still, in 1859, it was the 

 doctrine announced by M. Nicolet — based upon obser- 



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



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

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

 Aug. i86g, Jan. 1870, and Nov. 1871, PI. CIII. fig. vii.) ; whilst Prof. 

 A. M. Edwards of New York has recently ^-atched the conversion of 

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

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



* ' 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). 



