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Prof. Rudolf Virchow. The Position of [Mar. 16. 



quantity of which, in the form of energy, every living being is 

 endowed at the beginning of its life. 



The division of diseases, according to the amount of vital force 

 visible in them, into sthenic and asthenic, has never since been 

 abandoned, though acknowledged perhaps in a less precise manner ; 

 it has sometimes been brought more prominently forward, and some- 

 times thrown into the background. In Germany, Schonlein was the 

 one of all others who took this doctrine as the foundation for his 

 opinion on special cases of disease, and of his choice of treatment. 



But the application of the Brownian principles to physiology has 

 been of far greater importance. If life itself were dependent on 

 external stimuli, the notion of the spontaneity of vital actions, 

 a notion still in force, must lose all significance. Certain stimuli 

 would in that case prove to be necessary conditions of vital 

 activity, without which life could at best be carried on in a latent 

 form only. Certainly even for this latent life the question remained 

 open : How does it come to pass, and in what does it practically 

 consist ? Brown avoided this ticklish question, not without great 

 skill, by drawing the whole attention to active life and to the stimuli 

 which call forth action. To speak freely, science has since then 

 deflected little, if at all, from this guiding notion. Even now, 

 we cannot say what latent life is. We simply know that through 

 external stimuli it may be converted into active life, and hence irrit- 

 ability is considered by us as the surest sign of life, not of course of 

 the general life of all matter in the sense of Grlisson, but of the real and 

 individual life of special living organisms. Brown remarked, with 

 reason, that through irritability the living substance is differentiated 

 from the same substance in its dead condition, or from any other 

 lifeless matter. Nevertheless, neither irritability nor incitability, 

 neither irritation nor incitation, explains the essence of the living 

 substance, and therefore neither explains the essence of life. 



In Germany especially, the physiologists took up this question. 

 Among the first was Alexander von Humboldt, who in his various 

 writings, especially in his celebrated treatise on the irritated muscle 

 and nerve fibre, entered into the question. In the end he held fast 

 to the assumption of a vital force. The majority of pathologists and 

 physicians followed in his footsteps, and long and fierce controversies 

 were necessary before, nearly half a century later, the belief in a vital 

 force was destroyed. When du Bois-Reymond had demonstrated the 

 electrical current in muscle and nerve in all its characters, and, at 

 the end of his work, had also disclosed the inadmissibility of vital 

 force, then the venerable Humboldt formally and expressly renounced 

 the dream of his youth, with the masterly submission of the true 

 naturalist to the recognised natural law. 



The hypothesis of a particular force of life had, however, in regard 



