lo Mr. Faraday on 



discoveries relating to the phenomena of fermentation and 

 virulent diseases are directly the result of his conviction of 

 this radical difference between organic and inorganic 

 chemistry, springing out of his early researches into mole- 

 cular arrangement. This fact alone should cause us to 

 treat Pasteur's definition with very great deference. In 

 Pasteur's mind it is the compounding influence which is 

 life, while Dr. Tyndall's view would appear to be that life 

 is the result of the compound — whether of forces or of 

 matter we need not stop to inquire. Pasteur has always 

 been pre-disposed to look for life as a cause ; and in his 

 view life is an influence apart, the product of nothing but 

 itself 



Coming now to the discoveries of Faraday, Dr. Tyndall 

 observes : — " If the turning of the plane of polarisation be 

 a demonstration of molecular dissymmetry, then, in the 

 twinkling of an eye, Faraday was able to displace symmetry 

 by dissymmetry, and to confer upon bodies, which in their 

 ordinary state were inert and dead, this power of rotation 

 which M. Pasteur considers to be the exclusive attribute of 

 life." 



In this passage does not Dr. Tyndall lay himself open 

 to the charge of assuming that analogous effects are neces- 

 sarily due to identical states or causes, against which 

 assumption Faraday, in his paper, expressly cautions his 

 readers ? To take a simple illustration : I may lift a bar of 

 iron which may also be lifted by a magnet, but it does not 

 follow that because in both cases the iron is raised, therefore 

 the force which I exert is the same as that exerted by the 

 magnet, or that the state of myself and of the magnet are 

 the same. In comparing what Faraday himself calls 

 "natural" and "artificial" rotation, let us assume the beam 

 of light to be a ray of oscillating particles of ether. In 

 passing through the organic compound which has the 

 natural property of " rotating " the plane of such a ray, we 



