CHEMICAL CHANGES. 8 1 



combinations of living particles are also examples of 

 catalytic action. Because many actions have been attri- 

 buted to vitality which are unquestionably physical and 

 chemical, therefore all actions which are now regarded as 

 vital will ultimately be proved to be physical. Those who 

 argue in this way fail to perceive that they are dealing with 

 two different classes or kinds of actions. The truth is physics 

 and chemistry have never advanced one step in the direc- 

 tions indicated. . Great things have been done, but iri 

 altogether different lines of enquiry. Strange as it may 

 seem many undoubtedly high authorities have for years past 

 failed to distinguish between the act of construction in the 

 case of a machine or an organism, and the work performed 

 by it after its construction is complete. They have failed to 

 recognize any difference between formation and action, and 

 have forgotten that before an organ can act or perform its 

 function, it must be formed, and that its function and mode 

 of action are in great measure determined by the changes 

 which occurred during its formation. 



The power or force which is concerned in the formation 

 of an organ endowed with the most exquisite faculties is 

 supposed to be of the same essential nature as that which 

 causes certain kinds of matter to assume a definite cry- 

 stalline form. The formation of organs and structures 

 designed for the fulfilment of definite purposes which must 

 have been foreseen, as it were, from the earliest period of 

 development, is supposed to result from nothing more than 

 the action and reaction of the properties and forces of the 

 elements of matter concerned, and the external conditions 

 to which it is exposed. But it must be borne in mind that 



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