HEREDITY, VARIATION AND DEATH 39 



working hypothesis to account for it. But this fact which I 

 have already emphasised must be borne in mind, viz., that this 

 working hypothesis only provides us with a regulating principle. 

 Granting life as a fact and granting a tendency in living things 

 to vary, there are conditions that confine the flood of life within 

 definite channels and which have made the organic world what 

 it is. All this is of the very greatest interest, but it still leaves 

 life itself a mystery beyond our comprehension. It merely 

 pushes the mystery further and further back. Thus, it is not 

 now the colours of the butterfly, the legs of the antelope or the 

 brain of man, that most excite our wonder. It is the single 

 minute cell from which every individual, however complex, has 

 grown ; it is the one-celled organism from which all the higher 

 forms of life have been evolved. In the lowest known organisms 

 in which not even a nucleus can be seen is found potentially all 

 that makes the world varied and beautiful. In beings a little 

 higher in the scale the microscope has revealed an organisation. 

 It has shown us chromosomes or loops of chromatin which go 

 through astonishing kaleidoscopic changes and redistributions. 

 But if the germ-plasm within the nucleus is really the microcosm 

 it is believed to be and must be, there is an organisation altogether 

 indiscernible under the most powerful microscope. These chro- 

 matin loops must be made up of particles, each of which has a 

 character of its own, and each its proper place. Hence Weis- 

 mann's attempt to explain the architecture of the cell and all his 

 array of determinants and biophors. He has not introduced the 

 complication, but has tried to picture it. The complicated 

 arrangement of particles is there, an organisation so perfect that 

 the organisation of the German army compared with it is but 

 blunder and chaos. Yet Weismann's gallant attempt to organise 

 his army of innumerable biophors has often brought ridicule 

 upon his head. However, even if he fails, they organise them- 

 selves without his help. A propos of this we may recall the old 

 story of Galileo. When compelled to abjure his belief that the 

 earth went round the sun, he is said to have remarked, " But it 

 does for all that." Though he said it sotto voce, let us hope the 

 Pope heard it. So Weismann, if he is ever driven (an extremely 



