10 PHYSICAL CHEMISTRY IN MEDICINE. 



consequence that the energetic principle has really only 

 a formal significance, and can tell us nothing regarding 

 the quality of the process. This is apparent from its very 

 nature, namely, that of combining equivalents. With 

 what the numerical equivalence corresponds in any given 

 case, of this the law tells us nothing; just as little as 

 we know from the weight of an amount of gold what 

 kind of money it is, whether francs, marks, or guldens. 



The law of the conservation of energy could not help 

 but have from its very beginning an overwhelming 

 effect upon every investigator, not only because of 

 its great simplicity but also because of its unlimited 

 tenability in all subjects. 



It can seem little strange, therefore, that its heuristic 

 value has often been overestimated. It is certainly going 

 too far when, for example, a recognized medical historian 

 says of the law, " The discovery of the law of the con- 

 servation of energy has contributed no mean amount 

 toward disproving the vitalistic theory, that belief in a 

 peculiar vital force, and toward proving that the laws 

 of physics and chemistry suffice to explain all biological 

 and pathological phenomena." 



The darkness which envelops life phenomena cannot 

 be illuminated through any principle of mechanics. 

 For the time being, therefore, the belief in a vital force 

 must needs continue to exist. As in the case of the 

 other "forces" it too has had to bow to the law of energy, 

 but its death-blow will be received only when our knowl- 

 edge of natural phenomena will have attained a higher 

 development than at present. 



We have in the preceding paragraphs tried to go 



