THE DEDUCTIVE METHOD. 537 



moving in a straight line, by an induction from 

 instances in which the motion is deflected into a 

 curve, by being compounded with the effect of an 

 accelerating force. Notwithstanding the resources 

 afforded in this description of cases by the Method of 

 Concomitant Variations, the principles of a judicious 

 experimentation prescribe that the law of each of the 

 tendencies should be studied, if possible, in cases in 

 which that tendency operates alone, or in combina- 

 tion with no agencies but those of which the effect 

 can, from previous knowledge, be calculated and 

 allowed for. 



Accordingly, in the cases, unhappily very nume- 

 rous and important, in which the causes do not suffer 

 themselves to be separated and observed apart, there 

 is much difficulty in laying down, with due certainty, 

 the inductive foundation necessary to support the 

 deductive method. This difficulty is most conspi- 

 cuous in the case of physiological phenomena ; it 

 being impossible to separate the different agencies 

 which collectively compose an organised body, with- 

 out destroying the very phenomena which it is our 

 object to investigate : 



following life, in creatures we dissect, 



We lose it, in the moment we detect. 



And for this reason I am not quite prepared to agree 

 with M. Comte, in deeming the science of society 

 and government intrinsically a more difficult study 

 than the science of organic and animal life. I cannot 

 but incline to the opinion, that physiology is embar- 

 rassed by greater natural difficulties, and is probably 

 susceptible of a less degree of ultimate perfection, than 

 the social science ; inasmuch as it is possible to study 

 the laws of one man's mind and actions apart from 

 other men, much less imperfectly than we can study 



