276 NATURE AND LIFE. 



attention of physiologists a year ago ; the acetate of po- 

 tassa, and others. Hitherto the physiological virtues of 

 active principles have been studied only with respect to the 

 higher order of animals : Dumas pointed out the great 

 interest there would be in examining the influence they 

 exert over the lower organisms charged with the elabora- 

 tion of ferments, and over ferments themselves. Such re- 

 searches not only contribute to a better knowledge of the 

 mechanism itself according to which these principles affect 

 the system of vital phenomena, but they also gain the most 

 useful indications for the healing art. Indeed, beginning 

 with the moment at which Dumas and other chemists 

 made known the result of their examinations on this 

 subject, coincident also in time with the experiments of 

 Davaine on septicaemia, a vast number of attempts were 

 entered upon, in hospitals and in laboratories, to discover 

 to what extent these anti-fermenting substances hinder mor- 

 bid fermentations. These attempts are still proceeding; 

 we cannot foretell their success, but we are authorized 

 even now to say that they will not be barren of advantage 

 to the healing art. In this, as in all other departments of 

 scientific activity, we see abstract studies result in useful 

 discoveries. 1 



As a general statement of the subject, all this immense 

 work of fermentations, putrefactions, and corruptions of 

 organic matter, is effected in the world by a small number 

 of species of microscopic cells and filaments, by fungi and 

 spores of the lowest order, of which the germs fill our 

 atmosphere. This is one of the most certain acquisitions 

 of modern science, one of the most important from the 

 point of view of natural philosophy, one of the most pro- 

 ductive for those arts that are concerned in improving the 



1 Since these lines were written, silicate of soda, experimented on by 

 Rabuteau and myself, has taken a fixed place in the treatment of several 

 purulent and putrid disorders. 



