16 THEORIES OF LIFE. [iNTROD. 



and the vital actions exhibited by them, to a series of animating 

 principles (^rv%<u), differing according to the nature of the organized 

 bodies constructed by them, and acting under the direction of the 

 Supreme animating principle (c^ucrt?) . He supposes that eaCh par- 

 ticular kind of organized body had its proper animating principle, 

 or ^L%77, and that the variety of the former really depended upon 

 certain original differences in the nature of the latter, so that every 

 distinct species of animating principle would necessarily have its 

 appropriate species of body. 



Harvey, likewise, assumes the existence of an animating prin- 

 ciple, by which every organism is moulded into shape, out of mate- 

 rials furnished by the parent, and which, pervading the substance, 

 regulates the various functions of its corporeal residence. But, at a 

 subsequent stage of his inquiries, in assigning the blood as the special 

 seat of this principle, he advances another supposition totally at 

 variance with his previous hypothesis ; namely, that as, during the 

 development of the chick in ovo, the blood is formed and is 

 moved, before any vessel, or any organ of motion exists, so in it 

 and from it originate, not only motion and pulsation but animal 

 temperature, the vital spirit, and even (he principle of life itself. 

 So completely biassed were the views of this illustrious man, by 

 his exaggerated notions respecting the nature and properties of 

 the blood ! 



The celebrated John Hunter, who does not appear to have been 

 acquainted with the views expressed by Harvey, revived a some- 

 what similar hypothesis : and it is curious that the same fact should 

 have so attracted the attention of both as to have given the first 

 impulse to their speculations. This fact was, that a prolific egg 

 will remain sweet in a warm atmosphere, while an unfecundated 

 one will putrefy. The views of Hunter have been received with 

 very general favour by English physiologists. 



Hunter ascribes the phenomena of life to a materia vita, diffused 

 throughout the solids and the fluids of the body. This materia 

 vitce he considers to be " similar to the materials of the brain ; " he 

 distinguishes it from the brain by the title " materia vitce diffusa" 

 while he calls that organ " materia vita, coacervata," and sup- 

 poses that it communicates with the former through the nerves, 

 the chorda internuncia. And Mr. Abernethy, in commenting 

 upon these views, explains Mr. Hunter's materia vita to be a sub- 

 tile substance, of a quickly and powerfully mobile nature, which is 

 super added to organization and pervades organized bodies ; and this 

 he regards as, at least, of a nature similar to electricity. 



