PROFESSOH VIRQHOW AND EVOLUTION. C51 



are content to make your soul a poetic rendering of a 

 phenomenon which refuses the yoke of ordinary physical 

 laws, I, for one, would not object to this exercise of 

 ideality/"* Professor Virchow's meaning, I admit, re- 

 quired illustration; but I do not clearly see how the 

 quotation from me subserves this purpose. I do not even 

 know whether I am cited as meriting praise or deserving 

 opprobrium. In a far coarser fashion this utterance of 

 mine has been dealt with in other places: it may therefore 

 be worth while to spend a few words upon it. 



The sting of a wasp at the finger-end announces itself to 

 the brain as pain. The impression made by the sting 

 travels, in the first place, with comparative slowness along 

 the nerves affected; and only when it reaches the brain 

 have we the fact of consciousness. Those who think most 

 pofoundly on this subject hold that a chemical change, 

 which, strictly interpreted, is atomic motion, is in such a 

 case, propagated along the nerve, and communicated to 

 the brain. Again, on feeling the sting I flap the insect 

 violently away. What has caused this motion of my hand ? 

 The command from the brain to remove the insect travels 

 along the motor nerves to the proper muscles, and, their 

 force being unlocked, they perform the work demanded of 

 them. But what moved the nerve molecules which un- 

 locked the muscle? The sense of pain, it may be replied. 

 But how can a sense of pain, or any other state of conscious- 

 ness, make matter move? Not all the sense of pain or 

 pleasure in the world could lift a stone or move a billiard- 

 ball; why should it stir a molecule? Try to express the 

 motion numerically in terms of the sensation, and the 

 difficulty immediately appears. Hence the idea long ago 

 entertained by philosophers, but lately brought into special 

 prominence, that the physical processes are complete in 

 themselves, and would go on just as they do if conscious- 

 ness were not at all implicated. Consciousness, on this 

 view, is a kind of by-product inexpressible in terms of 

 force and motion, and unessential to the molecular changes 

 going on in the brain. 



Four years ago, I wrote thus: "Do states of conscious- 

 ness enter as links into the chain of antecedence and 



* Presidential address delivered before the Birmingham and Mid- 

 land Institute, October 1, 1877. Fwtnightly Review, Nov. 1, 

 1877, p. 607. 



