JOHANN MULLER 59 



ophical manner in which the material, swollen to vast proportions by 

 innumerable special researches was for the first time sifted and elab- 

 orated into a unitary picture of the mechanism within the living or- 

 ganism. In this respect the handbook is not only unsurpassed but 

 unequalled." 



To sum up and to sift the accumulated knowledge of a depart- 

 ment of scientific endeavor is truly a herculean task, one requiring 

 the impartiality of a judge and energy and zeal for the work that 

 amounts to genius. Haller performed a similar service for physiology 

 in his day. 



Johann Muller a "vitalist:" Attempts have been made to ac- 

 count in some more or less satisfactory way for the phenomena of life. 

 Two theories have engaged the attention of scientists — vitalism and 

 the chemico — physic or mechanistic theory. The majority of scien- 

 tists of the present day maintain that living organisms are mere 

 machines, as opposed to the theory of vitalism which presupposed the 

 presence of some "life" principle. The chemico-physicist today sees 

 nothing that may not be explained by the ordinary laws of physics 

 and chemistry. The tendency in all science is to express the less sim- 

 ple in terms of the more simple. Every activity of living substance 

 is accompanied by molecular or chemical changes in its composition, 

 such as oxidation (combustion) so that chemical activity, which is 

 the source of energy, and all vital manifestations are physico-chemical 

 in nature. Haller, in 1700, defined vitalism or vital force as a life 

 principle which possessed the ability to originate energy, which meant 

 that an organism was not wholly dependent upon the food which it 

 consumed for its energy. 



The scientists of the period 1810 to 1850 were, for the most part, 

 adherents to the mechanical explanation of the phenomena of life. 

 During this time also, the vitalistic theory was not without its advo- 

 cates who were among the pupils of the great idealist philosopher, 

 Schelling. Such men as Johann Muller, the physiologist; Von Baer, 

 the embryologist, and Liebig, the chemist, were said to be close ad- 

 herents to the vitalistic theory. It was not, however, until 1847, the 

 date of publication of the researches of Helmholtz on conservation of 

 energy that vitalism received a stunning blow. Sir Michael Foster A 

 explains Muller's vitalistic leanings by declaring that, "He was a 

 vitalist only in the sense that he was theoretically of opinion that 

 even when the physico-chemical analysis of vital phenomena had 

 been pushed as far as it could, there would still remain a large residue 

 which could not be explained by any such analysis, however complete.". 

 In view of the fact that his great pupils were noted for their effort to 

 solve physiological problems by physico-chemical means, the explana- 

 tion is plausible. It might be stated that Schwann, as well as other 

 pupils of Muller, had recourse to vitalistic explanations only 

 when their means of analysis proved inefficient. 



"The graven image, vitalism," says Starling, "has acted as a con- 

 tinual check on the growth of man's knowledge and control of his 

 environment just as the hypothesis of special creation would impede 

 all research into the relationships of animals and plants, so vitalism 

 would stay the hand of the physiologist in his endeavors to determine 

 the changes which occur within the living organism." 



