228 NATURE AND LIFE. 
Therapeutics has been aided, and may be more and 
more benefited, by the labors of physicists. The employ- 
ment of electricity, heat, cold, magnetism, and light, in the- 
treatment of diseases, is yet in its earliest stages, though 
momentous results have even now been gained. We shall 
need to study with careful exactness the action of these 
various forces on the human system. Are not these very 
forces closely linked to the cosmic medium in which we 
live, a medium swayed by the general conditions of celes- 
tial mechanism ? This is saying that the advance of medi- 
cal art is not independent of progress in investigations 
upon the relations of the organism with agents which seem 
to touch it but slightly, and from afar, 
Thus, history displays to our view all the sciences in 
constant mutual reaction, and completing their improve- 
ment by the reciprocation of .profound influences. It is 
thus that they sustain each other inseparably in commun- 
ion, and that the blended power of the whole gives at 
length, to the healing art as well as to industries of every 
other kind, increasing vigor and certainty. Such is the 
virtue of meditations and systematic experiments under- 
taken without any concern for the useful; but precisely 
because this manifold and painstaking evolution is _per- 
formed unconsciously, to those who are its workmen, under 
the influence of a small number of general ideas of which 
philosophy is the perpetual source, it results that the 
sciences, enriched by philosophy, minister in their turn 
to its advance and perfection.’ 
1 This essay may properly be completed by noting the labors which 
have lately led Rabuteau to suggest and recommend the protochloride 
of iron as that salt of iron which is most readily absorbed, and best 
adapted to the treatment of the many diseases in which preparations of 
iron are required. 

