170 NATURE AND LIFE. 



due to the rupture of the cells containing the coloring- 

 matter of the petals. This matter, freed from its cellular 

 covering, disappears on simply washing with water, and 

 the flower becomes almost white. In leaves showing two 

 surfaces of different shades, as the Begonia discolor, a kind 

 of mutual exchange of colors between the two surfaces 

 has been noticed. 



II. 



The physiological phenomena just spoken of are usually 

 confounded in books with the facts of electric medical 

 treatment, and it seems better to distinguish the two class- 

 es. The true method consists in first explaining the phe- 

 nomena displayed in the healthy organism, as the only way 

 of understanding afterward those that are peculiar to dis- 

 orders. Electric treatment forms a group of methods to 

 be classed among the most efficacious in medicine, pro- 

 vided they are applied by a practitioner well trained in the 

 theory of his art. Indeed, the most thorough physiologi- 

 cal knowledge is essential for the physician who would 

 make the electric currents erviceable. Mere experimenting, 

 even the most sagacious, must here be barren of good re- 

 sults a fact of which it is well to remind those who im- 

 pute to the method itself the failures it meets with in un- 

 skillful hands. It is true that, since the days of Galvani 

 and Volta, physicians have used galvanism in the treat- 

 ment of many diseases. Early in the century, galvanic 

 medicine was much talked of, and supposed to be the uni- 

 versal panacea. Galvanic societies, journals, and treatises, 

 undertook to spread its usefulness. The fashion lasted a 

 certain time, and would perhaps have growm indifferent, 

 when the discovery of induced electricity, due to Faraday, 

 in 1832, called professional attention once more to the vir- 

 tues of the electric fluid, and led to a new and interesting 

 range of experiments. Yet it is likely that the true sys- 



