30 PROGRESS OF SCIENCE IN THE CENTURY. 



read the same lesson. Far from being pre-occupied 

 with vivisection and inoculation, as the commonplace 

 summary too often suggests, he passed in an ever- 

 widening spiral of scientific investigation from his 

 rural centre upwards, from tanpit to vat and vintage, 

 from manure heaps, earth-worms, and water-supply 

 to the problems of civic sanitation. On each radius 

 on which he paused he left either a method or a clue, 

 and set some other enquirer at work. Biologist and 

 brewer, chemist and physician, agriculturalist and 

 surgeon, — and how many more — have all felt the 

 influence of his achievements, and part of the secret 

 of these lay in his sense of the correlation of knowl- 

 edge, in his grasp of the fact that workers in different 

 departments of science have much to say to each 

 other.* 



Another, and again a different illustration may be 

 found in the work of Darwin. It was natural that 

 one who discerned so vividly the correlation of or- 

 ganisms should also realise the correlation of knowl- 

 edge. We see this, for instance, as we turn over 

 the pages of The Origin of Species, The Descent 

 of Man, Variation under Domestication, and his 

 other great works, and infer from the foot-notes 

 something of the range of the fields in which he 

 gleaned. We see it in his recognition of the far- 

 reaching scope of the doctrine of descent, that it be- 

 longs not merely to the biologist, but affects psychol- 

 ogy and sociology, the whole life of man and society. 

 He once expressed satisfaction that he had not been 

 permitted to become a " specialist " ; it is hardly too 

 much to say that there is no specialism in concrete 

 organic science which he has left unaffected. 



* P. Geddes and J. Arthur Thomson, " Louis Pasteur," 

 Contemporary Review, Nov., 1895, pp. 632-644. 



