388 FRAGMENTS OF SCIENCE. 



forces which guide the molecules, into the special form 

 of the tree. In a general way, therefore, the life of the 

 tree might be denned as an unceasing effort to restore 

 a disturbed equilibrium. In the building of crystals 

 Nature makes her first structural effort; we have here 

 the earliest groping of the so-called ' vital force/ and 

 the manifestations of this force in plants and animals, 

 though, as already stated, indefinitely more complex, are 

 to be regarded of the same mechanical quality as those 

 concerned in the building of the crystal. 



Consider the cycle of operations by which the seed 

 produces the plant, the plant the flower, the flower again 

 the seed, the causal line, returning with the fidelity 

 of a planetary orbit to its original point of departure. 

 Who or what planned this molecular rhythm? We do 

 not know science fails even to inform us whether it 

 was ever ' planned ' at all. Yonder butterfly has a spot 

 of orange on its wing; and if we look at a drawing made 

 a century ago, of one of the ancestors of that butterfly, 

 we probably find the selfsame spot upon the wing. For 

 a century the molecules have described their cycles. 

 Butterflies have been begotten, have been born, and 

 have died; still we find the molecular architecture un- 

 changed. Who or what determined this persistency 

 of recurrence? We do not know; but we stand with- 

 in our intellectual range when we say that there is 

 probably nothing in that wing which may not yet find 

 its Newton to prove that the principles involved in its 

 construction are qualitatively the same as those brought 

 into play in the formation of the solar system. We 

 may even take a step further, and affirm that the brain 

 of man the organ of his reason without which he 

 can neither think nor feel, is also an assemblage of 

 molecules, acting and reacting according to law. Here, 

 however, the methods pursued in mechanical science 



