498 HISTORY OF PHYSIOLOGY. 



large advance with it; and it was because he was 

 so poised by the vast mass of his knowledge, so 

 temperate in his love of doubtM generalizations, 

 that he was not swept on in the wilder part of the 

 stream. To such a charge, moderate reformers, 

 who appreciate the value of the good which exists, 

 though they try to make it better, and who know 

 the knowledge, thoughtfulness, and caution, which 

 are needful in such a task, are naturally exposed. 

 For us, who can only decide on such a subject by 

 the general analogies of the history of science, it 

 may suffice to say, that it appears doubtful whether 

 the fundamental conceptions of affinity, analogy, 

 transition, and developement, have yet been fixed in 

 the minds of physiologists with sufficient firmness 

 and clearness, or unfolded with sufficient consistency 

 and generality, to make it likely that any great 

 additional step of this kind can for some time be 

 made. 



We have here considered the doctrine of the 

 identity of the seemingly various types of animal 

 structure, as an attempt to extend the correspond* 

 encies which were the basis of Cuvier's division of 

 the animal kingdom. But this doctrine has been 

 put forwards in another point of view, as the anti- 

 thesis to the doctrine of final causes. This ques- 

 tion is so important a one, that we cannot help 

 attempting to give some view of its state and 

 bearings. 



