;(g APPENBDt 



Sec. result from fhe Condition of the influence which this System, in its centre and dis 

 tributions, is instrumental in generating in the vessels and fluids which they contain. 

 May not a vital influence or atmosphere, as it were, be produced from the extreme 

 fibrillaB of this system, or between them ad the coats of the capillary vessels, which 

 influence, whatever may be its state of existence, impresses the fluid circulating- in 

 these vessels in a manner which produces different effects, according 1 to its excess or 

 defect, or according to other modifications to which it may be subject in health and 

 disease, owing to the numerous causes of change to which it is exposed ? 



27. The separation from the blood of the materials which supply the waste of the 

 textures, or give rise to their growth, is the office of this system, which imparts its in- 

 iiuence to, and operates through the medium of the vascular system. 



28. The vital manifestations of the veins and absorbents (with the exception of the 

 vena ports) arise from the distribution of the system of nerves to the minute arterial ca- 

 pillaries supplying their parictes, and to the adjoining textures; and, probably, from 

 the distribution of minute fibrillse to their tunics an org-anization which, although it can- 

 not be demonstrated, may nevertheless exist, and thus the vital manifestations of the 

 venous system may more readily be explained. 



29. The ganglial nerves sheathe the vena portse throughout its course in the liver ; and, 

 from the very abundant manner in which they supply this particular vein, from the con- 

 formation of the vein itself both as respects its coats and connexions with the texture 

 of the liver, and with the other vessels, and from the character of the blood conveyed 

 to and from it, we conclude, that it is through the vital influence bestowed on the 

 vena portse by the ganglial nerves, assisted with that belonging to the other vessels and 

 the textwe of this viscus, that the changes induced in the blood returned from the di- 

 gestive canal and its allied viscera, and containing a large proportion of absorbed mate- 

 rials, are produced ; and that the secretion of the bile results from the same influence, 

 partly as a consequence of these previous changes, and partly as its independent act 

 exerted both upon the extreme ramifications of the vena portse, and of the hepatic ar- 

 tery, this secretion consequently proceeding from both the kinds of blood contained by 

 these vessels. 



30. That this system of nerves, by means of the influence derived from its principal 

 nnd subordinate sources, and numerous distributions, and exerted upon the vascular 

 system, generates animal heat througout the body ; and that the production of animal 

 heat takes place in a manner analogous to the process of nutrition and secretion.* 



31. The state of animal heat, like other, secretions, will be greatly modified by the 

 condition, both as respects kind and degree, of the vital influence of the ganglial sys- 

 tem, and by the state of the blood on which this influence is exerted, which state will 

 have a double operation in modifying the result. (See the note on animal heat.) 



32. It appears probable, from the effects of several agents upon the voluntary and 

 other muscular parts, when applied immediately to the ganglial or vital system of nerves, 

 from the general distribution of this system to the capillary arteries, and from the cir- 



ing from the ganglial or vital class of nerves may be influenced, in the more perfect 

 animals, by the destruction of a part of the nervous system with which they have held, 

 and with which they always hold, a more or less intimate relation ; and that the same 

 nerves, which, during health, have conveyed a natural stimulus to the vital activity of 

 particular organs, may convey an artificial one : and when the natural stimulus or ex- 

 citant is removed, o"r the subordinate function annihilated, the operations to which it 

 is requisite, in the highest animals, must languish and ultimately decay. 



Indeed, it is only reasonable to suppose, that the involuntary nerves, as they commu- 

 nicate with the organic or vital nerves, convey a natural stimulus, or influence to the 

 latter, which, if they were deprived of it, after its continued and uninterrupted influx, 

 the vital functions of the organs enjoying this additional influence, would necessarily 

 languish, or even be overturned if the privation took place suddenly and completely. 

 If, however, it were brought about gradually, it might be produced to a great extent, 

 and in many animals completely. 



* The experiments of insulating a limb by dividing all the voluntary nerves and ar- 

 teries, excepting one arterial trunk, performed by Mr. Brodie, in order to ascertain the 

 effects produced upon the generation of heat in 'the lirnb, prove this proposition, and 

 could not fail of giving rise to what was actually observed. For the ganglial or vital 

 nerves supplying that'vessel could not be completely detached as long as any of the 

 coats of the artery remained undivided. 



