JOHANNES MULLER 529 



has been developed so far as to arouse in many the belief that psy- 

 chology should be taught as but a branch of physiology. That Miiller 

 saw so clearly the interrelation of these two branches of knowledge 

 is decidedly a point in his favor. His theories were upheld, moreover, 

 by the many facts presented in his works, " Concerning the Compara- 

 tive Physiology of the Sense of Sight in Man and the Lower Animals," 

 " Eegarding the Phantasmal Phenomena of Vision," also " Concerning 

 the Life of the Soul " ; and many other references in his " Handbook 

 of Physiology." 



Another, and perhaps the greatest, debt which the world of science 

 to-day owes to Miiller is for his establishment of physiology upon a 

 comparative basis. This conception did not first arise in Miiller, how- 

 ever, but was previously expressed by his teacher, Eudolphi, who had 

 already emphasized the motto: Comparative anatomy is the surest 

 support of physiology. Grasping the fuller significance of this thought, 

 Miiller worked throughout his life to uphold the view that phys- 

 iology can be only comparative; and among the vast number of his 

 physiological works, there are few in which this comparative principle 

 is not more or less clearly expressed. 



A further consideration of the nature of Miiller's work shows to 

 us the evident necessity of making one concession; and yet one which, 

 under careful examination, may not, after all, detract from the fame 

 which the world accords to him. This is the fact that in spite of 

 his varied activities Miiller was never able to make what we may call 

 a scientific discovery of the first rank. We can find issuing from his 

 hand no single observation which, as has often been the case with 

 other so-called great natural scientists, carries down with it through 

 the ages the name of the fortunate discoverer. With the names of 

 Priestley and Lavoisier will ever be linked the discovery of oxygen. 

 The mention of the name Harvey immediately brings to mind the 

 thought of the circulation of the blood, as with the name of Newton 

 we invariably associate the statements of the laws of gravity. But 

 discoveries of equal or even lesser importance can never distinguish 

 the name of Johannes Miiller. Even his excellent work on reflex 

 action and the function of the anterior and posterior spinal nerve roots 

 — these do not belong to him alone, for Charles Bell some years before 

 had already promulgated the theoretical law; yet it remained for 

 Miiller to prove this law, and by nice experimentation to establish its 

 universal application as a fact. Schwann presented to the world of 

 science that noteworthy discovery that the animal tissue, just as plant 

 organization, is composed of elemental cells; but it remained for 

 Miiller to show the highest importance attaching to this discovery, 

 and to lay down the law of the correspondence between embryonic and 

 pathological development. 



VOL. LXXII. — 34 



