344 LESSONS FEOM NATUEE. [CHAP. XI. 



not due to forces residing in the atmosphere only, but also in 

 the crystalline particles already deposited and in course of 

 deposition. 



&quot; Professor Tyndall s teaching differs widely from that of 

 Mr. Chauncey Wright. Speaking of the formation of pyra 

 midal crystals of salt, he says : 



&quot; The scientific idea is that the molecules act upon each other, .... 

 that they attract each other and repel each other at certain definite 

 points or poles, and in certain definite directions, and that the pyramidal 

 form is the result of this play of attraction and repulsion. * 



&quot; Mr. Wright seeks to refute the parallelism asserted by 

 Mr. Murphy and by me to exist between crystals and 

 organisms, saying : 



&quot; In organisms no doubt, as we may be readily convinced with 

 out resort to analogy, there is a great deal that is really innate, or 

 dependent on actions in the organism, which diversities of external 

 conditions modify very little, or affect at least in a very indeterminate 

 manner, so far as observation has yet ascertained. 



&quot; Here Mr. Murphy and I are fortunately at liberty to 

 invoke in our favour the authority, once more, of Professor 

 Tyndall, who can hardly be deemed even by Mr. Chauncey 

 Wright as incompetent in experimental philosophy, or as 

 likely to forget the age of the world in which he lives. In 

 the little work already quoted, he tells us :f 



&quot; This tendency on the part of matter to organize itself, to grow into 

 shape, to assume definite forms in obedience to the definite action of 

 force, is, as I have said, all-pervading. It is on the ground on which 

 you tread, in the water you drink, in the air you breathe. Incipient 

 life, as it were, manifests itself throughout the whole of what we call 

 inorganic nature. 



&quot; Speaking of a living grain of corn, and comparing it with 

 a crystal, he tells us we are bound to conclude that the 

 molecules of the corn are self-posited by the forces with 

 which they act upon each other. It would be poor philosophy 



* &quot; Essnys on the Use and Limit of the Imagination in Science 2nd 

 edition, 1871, p. 57. 

 f &quot; Ibid. p. 58. 



