MEMOIR OF MAGEMDIE. 119 



modern authors, was the theory of spirits derived from Galen. Galen, that 

 great theoretical cultivator of ancient physiology, had imagined spirits of three 

 kinds : the natural, which were formed in the liver ; the vital, which were 

 formec in the left ventricle of the heart ; and the animal or cerebral, which 

 were farmed in the brain. Willis very much simplifies matters ; with him, all 

 the spirits are formed in the brain : Statuimus has sjnritus soluvwiodo in ccrc- 

 hro ct ccrehcllo frocreari; all, it seems, are formed in the brain, and with not 

 much difficulty, as we shall see. It is, in fact, merely a chemical operation : 

 veltit in opus chimicum.^ The blood is carried into the brain and the cerebel- 

 lum by the narrow vessels of the plexus, as by the flexuous tubes of an alembic, 

 vcluti per ser2Jentinos alembici canal cs ; and then, in the substance of these two 

 organs, iiitra utriusque substantiam, the finest, most volatile and most subtle 

 particles are evolved from the blood ; these particles are the spirits. 



But do these spirits really exist ? This is the only question which Willis 

 forgets to propound ; for, in other respects, there are not a few which he pro- 

 ceeds to ask. He inquires why it is that these spirits, being so thin, so subtle, 

 so fitted for escaping — particulce ad acolandnm aptoi — do not in effect escape; 

 and he answers that they are confined or cohibitcd, to use his own expression, 

 by the membranes of the brain, as by the cap of an alembic — velut alembici 

 obductione. He even asks what they are — cpiid sint ? — and he avows that he 

 cannot venture to compare them too closely with the sjnrits of wine or of tere- 

 bintJi, seeing that these may be poured from one vessel into another, or even be 

 distilled, without being lost ; while, as for the animal S2nrits, they are so subtle 

 that after the death of the animal no traces of them are to be found. 



These animal spirits were the mysterious resource of all modern physiology, 

 from Descartes to Borden. t Borden having skilfully turned them into ridicule, 

 less use was made of them. Eventually, in the latter years of the last century, 

 a new term was substituted for the old one ; the animal spirits became the nervous 

 fluid. M. Cuvier still wrote in 1817 : "It seems to us that an explanation may 

 be rendered of all the phenomena of physical life by the simple admission of a 

 fluid such as we have just defined ; "J that is to say, the nervous fluid. 



Things were at this point, or nearly so, at the time when M. Bell began to 

 think for himself on the nervous system. " It was supposed," he says, " that 

 the brain secreted a nervous fluid, that the nerves were the channels which con- 

 veyed it, and that all were endowed with the same properties. With this appa- 

 rent simplicity of doctrine," he adds, *.' never has there been presented so great 

 a number of errors in the history of any science." 



The basis of this doctrine, so simple, as M. Bell justly remarks — for the 

 whole is here reduced to a single fluid — was the uniformity, the homogeneous- 

 ncss of action. For homogeneousness of action M. Bell substituted speciality 

 of action, and this Avas the first, the fundamental feature which separates his 

 theory from the old one. " The key," he says, " of my whole system will be 

 found in this single proposition : each filament of nervous matter is endowed 

 with a peculiar property independent of that of other filaments which occur along 

 with it, and this it preserves throughout its whole extent." {Natural System 

 of the Nerves of the Human Body.) 



The whole work of M. Bell is an analysis. From the date of his first essay, 

 in 1811,§ he separates and distinguishes the functions of the posterior roots of 

 the nerves from the functions of the anterior roots. This essay, too far in 

 advance of the physiologists of that day, attracted little or no notice ; the authoi-, 

 through discouragement, maintained silence for ten years. In 1S21 he resumed 



* Cerebri Anatome, cui Accessit Nervorum Dcscrip. «< Usiis. London, 1664. 

 t For tlie refutation of animal spirits by Borden, see my work entitled De la Vie ct de 

 V Intelligence, p. 43, &c. Paris, 1858. 



t Lc llcgnc Anirnal, &c., t. 1, p. 35, first edition. 



$ Idea oj' a New Anatomy of the Brain ; submitted for the observations of his friends. 



