256 THE BEGINNINGS OF LIFE. 



still a believer in Heterogenesis \ though it is some- 

 what doubtful whether he had rejected the old notions 

 as to the direct origin of the living from the not-living. 

 Although grave doubts may be entertained, therefore, as 

 to the propriety of expressing Harvey's doctrine by the 

 phrase omne vivum ex o<vo^ it is not even altogether free 

 from doubt whether the modification suggested by 

 M. Milne - Edwards, omne <ut*vum ex vivo, really em- 

 bodies the notion taught by Harvey. In illustration 

 of this difficulty, we need only quote the following 

 general statement made by Harvey in summing up his 

 doctrines 2 : c His autem omnibus (sc. animalibus et 

 stirpibus) . . . sive sponte, sive ex aliis, sive in aliis, 

 vel partibus, vel excrementis eorum putrescentibus, 



oriantur id commune est^ ut ex principio v'wente 



gignantur, adeo ut omnibus viventibus primordium insit 



ex quo et a quo proveniant Diversa scilicet 



diversorum viventium primordia; pro quorum vario 

 discrimine alii atque alii sunt generationis animalium 

 modi, qui tamen omnes in hoc uno conveniunt, quod 

 a primordio vegitali, tanquam e materia efficienti 

 virtute dotata, oriantur: differunt autem, quod prim- 

 ordium hoc vel sponte et casu erumpat, vel ab alio 

 praeexistente tanquam fructus proveniant.' Whilst 

 every living thing, therefore, is said to derive its im- 

 mediate origin from a c living principle,' Harvey also 



1 Attention was again prominently called to this fact in 1865, by M. 

 Pouchet. 



2 Loc. cit. p. 270. 



