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 ovo, it is not even altogether free 

 from doubt whether the modification suggested by 

 M. Milne - Edwards, omne vivum 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 - : 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 y ut ex principle vivente 



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 

 prseexistente 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. 

 Ponchet. 



2 Loc. cit. p. 270. 



