TRANSACTIONS OF SECTION I. 771 



Section I.— PHYSIOLOGY 

 PfiESiDES^T OF THE SEcnoN — Professor W. D. Halliburton, M.D., F.R.S. 



THURSDAY, SEPTEMBER 11. 

 The President delivered the following Address: — 



The Present Position of Chemical Physiology. 



An engineer who desires to thoroughly understand how a machine works must 

 necessarily know its construction. If the machine becomes erratic in its action 

 and he wishes to put it into proper working order, a preliminary acquaintance with 

 its normal structure and function is an obvious necessity. 



If we apply this to the more delicate machinery of the animal body we at 

 once see how a knowledge of function (physiology and pathology) is impossible 

 ■without a preliminary acquaintance with structure or anatomy. 



It is therefore not surprising, it is indeed in the nature of things, that physio- 

 logy originated with the great anatomists of the past. It was not until Vesalius and 

 Harvey by tedious dissections laid bare the broad facts of structure that any 

 theorising concerning the uses of the constituent organs of the body had any firm 

 foundation. 



Important and essential as the knowledge is that can be revealed by the 

 scalpel, the introduction and use of the microscope furnished physiologists with a 

 still more valuable instrument. By it much that was before unseen came into 

 view, and microscopic anatomy and physiology grew in stature and knowledge 

 simultaneously. 



The weapons in the armoury of the modern physiologist are multitudinous in 

 number and complex in construction, and enable him in the experimental investi- 

 gation of his subject to accurately measure and record the workings of the different 

 parts of the machinery he has to study. But pre-eminent among these instruments 

 stands the test-tube and the chemical operations typified by that simple piece of 

 glass. 



Herein one sees at once a striking distinction between the mechanism of a 

 living animal and that of a machine like a steam engine or a watch. It is quite 

 possible to be an excellent watchmaker or to drive a steam engine intelligently 

 without any chemical knowledge of the various metals that enter into its composi- 

 tion. In order to set the mechanism right if it goes wrong all the preliminary 

 knowledge which is necessary is of an anatomical nature. The parts of which an 

 engine is composed are stable ; the oil that lubricates it and the fuel that feeds it 

 never become integral parts of the machinery. But with the living engine all this 

 is different. The parts of which it is made take up the nutriment or fuel and 

 assimilate it thus building up new living substance to replace that which is 

 destroyed in the wear and tear associated with activity. This condition of 

 unstable chemical equilibrium is usually designated metabolism, and metabolism 

 is the great and essential attribute of a living as compared with a non-living thing. 



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