RESULTS AND LIMITS OF SCIENTIFIC METHOD. 463 



of phenomena there can be no causal or genetic connexion.' 

 Living forms as we now regard them are essentially 

 variable. Now from constant mechanical causes constant 

 effects would ensue. If vegetable cells are formed on 

 geometrical principles, being first spherical, and then by 

 mutual compression dodecahedral, then all cells should 

 have similar forms. In the Foraminifera and some other of 

 the more lowly organisms, we do seem to observe the pro- 

 duction of complex forms on pure geometrical principles. 

 But from similar causes acting according to similar laws 

 and principles, only similar results could be produced. If 

 the original life-germ of each creature is a simple particle 

 of protoplasm, unendowed with any distinctive forces, then 

 the whole of the complex phenomena of animal and vege- 

 table life are effects without causes. Protoplasm may be 

 chemically the same substance, and the germ-cell of a 

 man and of a fish may be apparently the same, so far as 

 the microscope can decide ; but if certain cells produce 

 men and others as uniformly produce a given species of 

 fish, there must be a hidden constitution determining the 

 extremely different results. If this were not so, the 

 generation of every living creature from the uniform 

 germ would have to be regarded as a distinct act of 

 arbitrary creation. 



! Theologians have dreaded the establishment of the 

 theories of Darwin and Spencer, as if they thought that 

 those theories could explain everything upon the purest 

 mechanical and material principles, and exclude all notions 

 of design.^ They do not see that those theories have 

 opened up more questions than they have closed. I The 

 doctrine of evolution gives a complete explanation of no 

 single living form. ) While showing the general principles 

 which prevail in the variation of living creatures, it only 

 points out the infinite complexity of the causes and cir- 

 cumstances which have led to the present state of things. 



