ADDRESS. 15 



The Specific Energies of the Organism. 



When in 182o J. Miiller was engaged in investigating the physiology 

 of vision and hearing he introduced into the discussion a term, ' specific 

 energy,' the use of which by Helmholtz ' in his physiological writings has 

 rendered it familiar to all students. Both writers mean by the word 

 energy, not the ' capacity of doing woi^k,' but simply activity, using it in 

 its old-fashioned meaning, that of the Greek word from which it is de- 

 rived. With the qualification ' specific ' it serves, perhaps, better than any 

 other expression to indicate the way in which adaptation manifests itself. 

 In this more extended sense the ' specific energy ' of a part or organ — 

 whether that part be a secreting cell, a motor cell of the brain or 

 spinal cord, or one of the photogenous cells which produce the light 

 of the glowworm, or the protoplasmic plate which generates the dis- 

 charge of the torpedo — is simply the special action which it normally 

 performs, its norma or rule of action being in each instance the interest 

 of the organism as a whole of which it forms part, and the exciting cause 

 some influence outside of the excited structure, technically called 

 a stimulus. It thus stands for a characteristic of liviner structures 

 which seems to be universal. The apparent exceptions are to be found in 

 those bodily activities which, following Bichat, we call vegetative, because 

 they go on, so to speak, as a matter of course; but the more closely we 

 look into them the more does it appear that they form no exception to the 

 general rule, that every link in the chain of living action, however uniform 

 that action may be, is a response to an antecedent influence. Nor can it 

 well be doubted that, as every living cell or tissue is called upon to act in 

 the interest of the whole, the organism must be capable of influencing 

 every part so as to regulate its action. For, although there are some in- 

 stances in which the channels of this influence are as yet unknown, the 

 tendency of recent investigations has been to diminish the number of such 

 instances. In general there is no diSiculty in determining both the 

 nature of the central influence exercised and the relation between it and 

 the normal function. It may help to illustrate this relation to refer to the 

 expressive word Auslosung by which it has for many years been designated 

 by German writers. This word stands for the performance of function by 

 the ' letting off"' of ' specific energies.' Carrying out the notion of ' letting 

 off'' as expressing the link between action and reaction, we might com- 

 pare the whole process to the mode of working of a repeating clock (or 

 other similar mechanism), in which case the pressure of the finger on the 

 button would represent the external influence or stimulus, the striking 

 of the clock, tbe normal reaction. And now may I ask you to consider 

 in detail one or two illustrations of physiological reaction — of the letting 

 off of specific energy ? 



' Handh. der physiologischen Optik, 1886, p. 233. Helmholtz uses the word in 

 the plural — the ' energies of the nerves of special sense.' 



