358 LAMARCK, BIS LIFE AND WORK 



" However, were it not for the picture that so 

 many celebrated men have drawn of the weakness 

 and lack of human reason; were it not that, inde- 

 pendently of all the freaks into which the passions 

 of man almost constantly allure him, the igtioratice 

 which makes him the opinionated slave of custom 

 and the continual dupe of those who wish to deceive 

 him ; were it not that his reason has led him into 

 the most revolting errors, since we actually see him 

 so debase himself as to worship animals, even the 

 meanest, of addressing to them his prayers, and of 

 imploring their aid; were it not, I say, for these 

 considerations, should we feel authorized to raise 

 any doubts as to the excellence of this special light 

 which is the attribute of man ? 



" An observation which has for a long time struck 

 me is that, having remarked that the habitual use 

 and exercise of an organ proportionally develops 

 its size and functions, as the lack of employment 

 weakens in the same proportion its power, and even 

 more or less completely atrophies it, I am apprised 

 that of all the organs of man's body which is the 

 most strongly submitted to this influence, that is to 

 say, in which the effects of exercise and of habitual 

 use are the most considerable, is it not the organ of 

 thought — in a word, is it not the brain of man ? 



" Compare the extraordinary difference existing 

 in the degree of intelligence of a man who rarely ex- 

 ercises his powers of thought, who has always been 

 accustomed to see but a small number of things, 

 only those related to his ordinary wants and to his 

 limited desires; who at no time thinks about these 

 same objects, because he is obliged to occupy him- 

 self incessantly with providing for these same wants; 

 finally, who has few ideas, because his attention, 

 continually fixed on the same things, makes him 

 notice nothing, that he makes no comparisons, that 

 he is in the very heart of nature without knowing it, 



