OBSERVATION AND EXPERIMENT. 41 



way of saying that the science of life is in its youth. 

 Sciences begin in casual observation and systematic 

 reasoning. Careless of facts, men are then careful in 

 logic. They build elaborate structures upon shifting- 

 sand. Afterwards arrives the epoch of doubt ; men 

 become aware how illusory is the reliance on reason- 

 ing, be it never so logical, unless the data are exact, 

 unless each step has been verified. The scrutiny of 

 facts becoming more urgent, Observation ceases to be 

 casual and careless ; a cultivated caution takes its 

 place, and conclusions are tested less by their logical 

 coherence than by their verified dependence on veri- 

 fied facts. Now the most puissant instrument of veri- 

 fication is the Experimental Method which, by- a pro- 

 cess of elimination and exclusion, directly interrogates 

 Nature. 



You thus perceive that time is not likely to hang 

 heavy on our hands, while at the coast ; there is enough 

 to do and to enjoy. Dr Johnson said that he who 

 would acquire a pm^e English style must give his days 

 and nights to Addison. I have some doubts whether 

 the prescription is likely to be followed, or, if followed, 

 likely to eff'ect its purpose ; but its language may be 

 borrowed to suit my turn. He who would learn the 

 exquisite delights Nature has for those who ardently 

 pursue her, and would acquire a deep sense of rever- 

 ence and piety in presence of the great and unfathom- 

 able mysteries which encompass Life, must give his 

 mornings to laborious searchings on the rocks, his 

 afternoons to patient labour with the Microscope. 



