VICTORY AND REST 171 



experiment, and vast collections of minute facts. The 

 difference is strikingly characteristic of the strong point 

 of Darwin's genius. While he had all the breadth and 

 universality of the profoundest thinkers, he had also all 

 the marvellous and inexhaustible patience of the most 

 precise and special microscopical student. 



For years, indeed, Darwin studied the ways and 

 instincts of the common earthworm with the same close 

 and accurate observation which he gave to every other 

 abstruse subject that engaged in any way his acute 

 intellect. The lawyer's maxim, ' De minimis lex non 

 curat,' he used to say, never truly applies to science. 

 As early as the year 1837 he read a paper, before the 

 Geological Society of London, ' On the Formation of 

 Mould,' in which he developed with some fulness the 

 mother idea of his complete theory on the earthworm 

 question. He there showed that layers of cinders, marl, 

 or ashes, which had been strewn thickly over the surface 

 of meadows, were found a few years after at a depth of 

 some inches beneath the turf, yet still forming in spite 

 of their burial a regular and fairly horizontal stratum. 

 This apparent sinking of the stones, he believed, was 

 due to the quantity of fine earth brought up to the 

 surface by worms in the form of castings. It was ob- 

 jected to his theory at the time that the work supposed 

 to be accomplished by the worms was out of all reason- 

 able proportion to the size and numbers of the alleged 

 actors. Here Darwin's foot was on his native heath ; 

 he felt himself immediately on solid ground again. 

 The cumulative importance of separately infinitesimal 

 elements is indeed the very keynote and special pecu- 

 liarity of the great biologist's method of thinking. He 



