HOUSE-SURGEON AT THE CHARITE 27 



day, or to ask him where I could meet him to hear the results 

 of these experiments, if he is unable to lend it? J and in spite 

 of the heavy work of the summer months on the out-patient 

 post at the Charite, he adds, ' I am now so far advanced with 

 my experiments that I am ready to begin writing, and it is 

 essential to acquaint myself with the work of Mitscherlich.' 



The main object of this paper, published in Mutter's Archiv 

 in 1843, with the title 'On the Nature of Fermentation and 

 Putrefaction ', was to support Liebig in his attack on vitalism 

 by proving that there can be no such thing as spontaneous 

 generation. Helmholtz found, however, that the transforma- 

 tions known as fermentation and putrefaction are not the result 

 of chemical action, as supposed by Liebig, and therefore due 

 \ to the action of oxygen, or the introduction of residual dis- 

 integration products of the putrefying substances. He showed 

 (and the clear and precise wording of his results is of especial 

 interest in view of the great discoveries of Pasteur at a later 

 time) that putrefaction can occur independently of life, but 

 that it offers a fertile soil for the development and nutrition 

 of living germs, and is modified in its aspects by them. 

 Fermentation is one such putrefactive process modified by 

 organisms, and correlated with them ; it strikingly resembles 

 the vital process in the similarity of the substances it attacks, 

 in its rate of growth, and the similarity of the conditions 

 determining its continuance or check. 



These observations, which Helmholtz was unable to pursue 

 from the inadequacy of the means at his command, seemed 

 actually to give fresh support to vitalism, and his experiments 



were accordingly regarded with suspicion, above all by the 

 physicists. Magnus, indeed, whose generous liberality knew 

 no scientific jealousy, invited him to make use of his private 

 laboratory, and to take advantage of ' methods of investigation 

 that would throw more light on the subject than such as a 

 young army surgeon living on his pay could provide for him- 

 self; but it was not until two years later that Helmholtz was 

 table to convince him by a series of new experiments of the 

 accuracy of his previous work. Nor did he publish anything 

 iirther on the subject, which had occupied him almost daily 

 : or three months. He was already engaged on other and far 

 profounder problems, the solution of which was to condemn 



