242 FOOTNOTES FROM 



indefinitely ; thus showing the close and intimate con- 

 nexion subsisting between plants that in other circum- 

 stances are widely different, when placed under similar 

 conditions. Such instances as these may be regarded as 

 circumstantial evidence in favour of Darwin's famous 

 theory of the origin of species by natural selection, that 

 is, that all existing plants have descended from three or 

 four progenitors, or even from one primordial form into 

 which life was first breathed by the Creator ; the vast 

 modification which these plants now exhibit being mainly 

 the result of a process of natural selection carried on 

 during vast geological periods and epochs of time. No 

 human intellect, however, unaided by revelation, is at 

 present able to make such conclusions as these matters of 

 positive proof or positive refutation. They must remain 

 a question of opinion, in the discussion of which peculi- 

 arities of mind and education must largely operate as bias- 

 sing influences ; a kind of Penelope's web, which, however 

 skilfully woven by one, will be ruthlessly unwoven by an- 

 other, until a more solid and enduring fabric has been put 

 together in the loom by some more competent artist. 



A still more striking form of the protean mould under 

 consideration, is that which occurs in the fermenting of 

 yeast and other substances. It may surprise many to be 

 told that yeast is merely an undeveloped condition of the 

 common mould which they see on their bread and cheese. 

 Fermentation is in one sense a chemical process, forming 

 the first step towards dissolution, or that re-arrangement 

 of old elements which is necessary to form new com- 

 pounds ; but, strange to say, the action is -also vegeta- 

 tive. The whole mass of fermenting matter gradually 



