28 THE GERM THEORY OF DISEASE. 



a transformation of the oxamide, which is decomposed into 

 oxalic acid and ammonia. As much oxalic acid exists after 

 the decomposition as was added, and still possesses its original 

 power; and more oxamide will be decomposed in the same 

 way, if added. This may be kept up continuously, and any 

 amount of the oxamide decomposed, by a very minute por- 

 tion of the oxalic acid. 



Quite a number of similar chemical decompositions are 

 known, and while they cannot be considered as bodies in a 

 state of decomposition, as Liebig claimed the excitors of 

 fermentation were, the processes had long been considered as 

 very closely related. Now as these processes were admitted 

 by all to be purely chemical, no process should be considered 

 vital until it was definitely proven. 



This required that each one of these be investigated on its 

 own merits and proven independent of all others. 



In this work the theory has, perhaps, suffered as much from 

 its over-zealous followers, who hastily published untenable 

 views, arrived at by hasty and ill-digested experiments, as 

 from its opponents. 



SCHROEDER. 



Schroeder was, perhaps, the first to make a new and sub- 

 stantial point that has stood the test of adverse criticism. As 

 we have stated, Schwan had demonstrated that decomposition 

 would not occur in sterilized fluids upon the introduction of 

 air that had been heated or passed through sulphuric acid. 

 This, as a demonstration of the existence of life, was appa- 

 rently demolished by Liebig, who claimed that the heat, or the 

 acid either, was sufficient to destroy the molecular motion upon 

 which, as he claimed, the power of ferments depended. Now 

 Schroeder, in 1854, admitted air filtered through cotton 

 batting, with the idea that this would catch any solid par- 

 ticles in the shape of spores or germs. His experiment was a 



