SOCIETY OF PHYSICS AND NATURAL HISTORY, OF GENEVA. 343 



laboratory of Flonreus, he was called to Birmiiigliam to occui)y a chair 

 of physiology and a position as physician to the hospital of that city. 

 ' He even tljen felt the first symptoms of the diseases which subsequently 

 carried him off, and was obliged to give up some of his labors on account 

 of his failing' health. He next removed to Switzerland, and after having 

 lived in the Canton Vaud for several years, he came in l.SGSto reside in 

 Geneva. 



Although Waller had been obliged to abandon his regular labors, his 

 mind, unusually active and ingenious, could not remain idle, and he 

 never entirely ceased to occupy himself with interesting questions in 

 physiology and medicine. At Geneva, his health having improved, he 

 devoted himself anew to medical practice, to which he was always much 

 attached, and his large experience in that line rendered him especially 

 eminent. In 18G9 he was received as a member of our society. The 

 same year he had the honor of being invited to d(^liver the Crooniau 

 lecture to the Royal Society of London, and for that purpose rej)aired 

 to England. His health, which appeared to be confirmed, was not 

 established. He had suffered several severe attacks of quinsy, a malady 

 which suddenly terminated his existence on the 18th of September, 1870, 

 at the age of fifty-five years. 



It would take too much time to analyze all the labors of our lamented 

 associate; we shall limit ourselves to a short summary of those which 

 have excited the most interest iu the scientific world, particularly his 

 work upon the degeneracy of the nerves. The nerves which are 

 distributed through different parts of the body are, we know, composed 

 of diiferent fibers, intermixed with each other — those which call into 

 action motive-power, and those which convey impressions of sensibility. 

 At their origin, that is to say at their iioint of emergence, from the 

 spinal marrow, the motor nervous fibers are separated from the sensitive 

 nervous fibers ; the former constituting the anterior roots and the Intter 

 the posterior. After having demonstrated by experiment that when a 

 complex nerve is cut, the outer segment, suddenly arrested, withers and 

 degenerates, while the central segment, remaining iu communication 

 with the nervous center, continues unchanged, Waller studied the 

 degeneration of the nerves taken at their origin. Beginning at the 

 nervous roots, he proved that the nervous center, which maintains 

 intact the nervous fibers of the anterior roots, is seated iu the spinal 

 marrow itself, while the nervous center, which contiimes intact the 

 nervous fibers of the posterior roots, is situated in the intervertebral 

 ganglion, united to their posterior roots. It was by means of sec- 

 tions of these roots taken at difierent distances, that Waller made 

 these important discoveries, the application of which immediately 

 occurred to him. The changes which take place in the structure of a 

 nerve after the cutting are so evident that the experimenter can avail 

 himself of it as a means of tracing the distribution of their fibers in the 

 different tissues. It is in this way that he succeeded iu perceiving the 



