506 HISTORY OF PHYSIOLOGY. 



sagacity and impartiality, can tell us what is the 

 general tendency of the best researches on this sub- 

 ject 11 . But when the anatomist expresses such 

 opinions, and defends them by such illustrations as 

 those which I have just quoted 12 , we perceive that 

 he quits the entrenchments of his superior science, 

 in which he might have remained unassailable so 

 long as the question was a professional one ; and 

 the discussion is open to those who possess no pecu- 

 liar knowledge of anatomy. We shall, therefore, 

 venture to say a few words upon it. 



Sect. 2. Estimate of the Doctrine of Unity of Plan. 



IT has been so often repeated, and so generally 

 allowed in modern times, that final causes ought 

 not to be made our guides in natural philosophy, 

 that a prejudice has been established against the 

 introduction of any views to which this designation 

 can be applied, into physical speculations. Yet, in 



11 So far as this doctrine is generally accepted among the best 

 physiologists, we cannot doubt the propriety of Meckel's re- 

 marks, (Comparative Anatomy, 1821, Pref. p. xi.) that it cannot 

 be truly asserted either to be new, or to be peculiarly due to 

 Geoffrey Saint-Hilaire. 



12 . It is hardly worth while answering such illustrations, but 

 I may remark, that the one quoted above, irrelevant and unbe- 

 coming as it is, tells altogether against its author. The fact that 

 the wooden leg is of the same length as the other, proves, and 

 would satisfy the most incredulous man, that it was intended 

 for walking. 



