PROBLEMS OF BIOLOGY 311 



trix, of the older physiologists, the Bildungstrieb of Blumen- 

 bach, the Lebenskraft of Paracelsus, Stahl and Treviranus, 

 ' shaping the physical forces of the body to its own ends,' 

 ' dreaming dimly in the grain of the promise of the full corn 

 in the ear' 1 (to borrow the rendering of an Oxford 

 scholar), these and many more, like Driesch's * Entelechy ' 

 of to-day, are all conceptions under which successive genera- 

 tions strive to depict the something that separates the earthy 

 from the living, the living from the dead. And John Hunter 

 described his conception of it in words not very different from 

 Driesch's, when he said that his principle, or agent, was 

 independent of organisation, which yet it animates, sustains, 

 and repairs ; it was the same as Johannes Muller's concep- 

 tion of an innate ' unconscious idea.' 



Even in the Middle Ages, long before Descartes, we can 

 trace, if we interpret the language and the spirit of the time, 

 an antithesis that, if not identical, is at least parallel to our 

 alternative between vitalistic and mechanical hypotheses. 

 For instance, Father Harper tells us that Suarez maintained 

 that in generation and development a Divine Interference is 

 postulated, by reason of the perfection of living beings; in 

 opposition to St Thomas, who (while invariably making an 

 exception in the case of the human soul) urged that, since 

 the existence of bodily and natural forms consists solely in 

 their union with matter, the ordinary agencies which operate 

 on matter sufficiently account for them. 2 



1 Cit. Jenkinson (Art. 'Vitalism ' in Hibbert Journal, April 1911), who has given 

 me the following quotation: 'Das Weitzenkorn hat allerdings Bewusstsein dessen 

 was in ihm ist und aus ihm werden kann, und traiimt wirklich da von. Sein Bewusstsein 

 und seine Traiime mogen dunkel genug sein ' ; Treviranus, Erscheinungen und Gesetze 

 des organischen Lebens, 1831. 



2 ' Cum formarum naturalium et corporalium esse non consistat nisi in unione ad 

 materiam, ejusdam agentis esse videtur eas producere, cujus est materiam trans- 

 mutare. Secundo, quia cum hujusmodi formae non excedant virtutem et ordinem et 

 facultatem principiorum agentium in natura, nulla videtur necessitas eorum originem 

 in principia reducere altiora.' Aquinas, De Pot. Q., Hi. a 11. Cf. Harper, Metaphysics 

 of the School, iii. 1, p. 152. 



