THE BIOLOGY OF DAILY LIFE. 65 



consequences of this assumption by the appli- 

 cation of such general principles as the case 

 admits ; comparing them in succession with all 

 the particular cases within our knowledge ; and 

 lastly, on this comparison, so modifying and re- 

 stricting the general enunciation of our laws as 

 to make the results agree" 



It is by the third of these methods that I have set 

 to work upon the "bold hypothesis," or rather 

 " assumption," which may be briefly named the " pro- 

 toplasm theory." We shall find, I believe, that that 

 theory must be greatly modified before it can be 

 accepted as representing a law of Nature. I shall 

 state it in this modified form in the course of this 

 chapter, now I proceed to the examination of the 

 hypothesis itself. 



But before I begin, let me confess my fears. I 

 know well I am trying to approach the dearest " Idol 

 of the (Biological) Theatre."* I am much encouraged 

 by the words of Dr. Burdon Saunderson, who callsf 

 protoplasm " a worn out Deus ex machina," and 

 denies that it avails to explain the phenomena of 

 function in living organisms. 



* " There is also a fourth kind [of illusions] which we denomi- 

 nate Idols of the Theatre, and is superadded from false theories 

 or systems of philosophy, and erroneous laws of demonstration." 

 (Bacon's Advancement of Learning, Book v., chap. 4.) 



f At the Newcastle meeting of the Brit. Assoc., in Sept., 1889. 

 " Whenever this point" [viz., when we are " face to face with 

 functional differences which have no structural difference to 

 explain them") "is arrived at in any investigation structure 

 must for the moment cease to be our guide, and in general two 

 courses or alternatives are open to us. One is to fall back on 

 that worn out Deus ex machina, protoplasm, as if it afforded a 



F 



