390 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 c 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 

 unchanged. Who or what determined this persis- 

 tency of recurrence? We do not know; but we 

 stand within 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 prin- 

 ciples 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 



