72 Hidorical Notices in regard to the Distinction of Nerves 



column, are nerves of involuntary motion — of vittility. A homogeneous 

 nerve does not, as a totality, perform a single office ; for every elementary 

 fibril of which it is composed runs from first to last isolated from every 

 other, and has its separate sphere of exercise. As many distinct spheres 

 of sensation and motion/so many distinct nervous origins and termina- 

 tions ; and as man}^ different points of local termination in the body, so 

 many different points of local origin in the brain. The Sensorium Com- 

 mune, the centre of sensation and motion, is not therefore an indivisible 

 point, not even an undivided place ; it is, on the contrary, the aggregate of 

 as many places (and millions of millions there may be) as there are encepha- 

 lic origins of nervous fibrils. No nerve, therefore, in propriety of speech, 

 gives off a branch ; their sheaths of dura mater alone are ramified ; and 

 there is no intercourse, no sympathy between the elementary fibrils, ex- 

 cept through the sensorium commune. Ihat the nerves are made up of 

 fibrils is shewn, though inadequately, by various anatomical processes ; 

 and that these fibrils are destined for distinct and often different purposes, 

 is manifested by the phsenomena of disjoined paralysis and stupor. (De 

 Morbis Nervorum Prselectiones, by Van Eems, pp. 261, 490-497, 696, 

 713-717. Compare Kaaii Boerhaave, Impetum Faciens, § 197-200.) 



The developed doctrine of Boerhaave on this point is to be sought for, 

 neither in his Aphorisms, nor in his Institutions and his Prelections on 

 the Institutions — the more prominent works to which his illustrious dis- 

 ciples,HALLER and Van Swieten, appended respectively a commentar3\ — 

 Of these, the latUr adopts, but does not advance, the doctrine of his 

 master. (Ad Aph. 701, 711, 774, 1057, 1060.)— The former, who, in his 

 subsequent writings, silently abandoned the opinion, that sensation and 

 motion are conveyed by different nervous fibrils, in two unnoticed pas- 

 sages of his annotations on Boerhaave (1740), propounds it as a not im- 

 probable conjecture — that a total nerve may contain within its sheath a 

 complement of motory and of sensitive tubules, distinct in their origin, 

 transit, and distribution, but w hich at their peripheral extremity com- 

 municate ; the latter, like veins, carrying the spirits back to the brain, 

 which the former had, like arteries, carried out. (Ad Boerh. Instit. § 

 288, n. 2, § 293, n. 2..) 



The doctrine of the school of Leyden, on this point, was, however, still 

 more articulately evolved by the younger (Bernard Siegfried) Albinus ; 

 • not in any of his published works, but in the prelections he delivered for 

 many years, in that university, on Physiology. From a copy in my pos- 

 session of his dictata in this course, very fully taken, after the middle of 

 the century, by Dr William Grant (of Rothiemurchus), subsequently a 

 distinguished medical author and practical physician in London, compar- 

 ed with another very accurate copy of these dictata, taken by an anony- 

 mous writer, in the year 1741 ; I am enabled to present the following 

 general abstract of the doctrine taught by this celebrated anatomist, 

 though obliged to retrench both the special cases, and the reasoning in 

 detail by which it is illustrated and confirmed. 



