14 APPENDIX. 



when the vital actions of capillary vessels are increased, the vessels themselves become 

 larger, more fully injected, and circulate a larger quantity of blood. Now, if we allow 

 that an increase in degree forms one part of the change in the vital influence bestowed 

 on the capillaries by the ganglial neives, it therefore follows that a proportionate change 

 in the calibre of the minuter vessels should result from such increase as it usually does 

 on those occasions when it supervenes in a-natural manner. 



In shert that one of the changes constituting the acute stage of inflammation is an ex- 

 alted state of the vital influence distributed by the ganglial nerves to the capillaries of 

 the part ; an exalted state of this influence always increases the action and caliber of the 

 capillaries, therefore both must be increased whenever this condition of vital influences 

 constitutes a part of the primary derangement. 



But it has been argued, that when an inflamed capillary is viewed in a microscope, 

 the current of blood in it is slower, instead of being quicker, than natural. This, how. 

 ever, arises, as we have stated on another occasion, from the inflamed capillarv vessels 

 admitting a greater number of red globules, and thus giving rise to the optical illusion 

 of their slower motion, when in fact they actually move much quicker than when the 

 vessel admits a single globule at a time, and when the entire space between each glo- 

 bule moving in the vessel can be seen. Another objection has been urged in support 

 of the l^pothesis of relaxation or debility of the vessels, namely, that the exposed ca- 

 pillaries contract upon the application of an irritant; but so do all irritable parts, and so 

 do all parts, to a greater or less extent, which are supplied with the vital influence. la 

 these experiments it has not been considered, because it was unfavourable to the hypo- 

 thesis, that the irritant acts in a two-fold capacity ; it excites irritable fibres to contraction, 

 and it constringes the structure of the part. These experiments also appear generally 

 to have been performed under circumstances of disorder, and at a period when the in- 

 flammation was passing into that stage which is constituted by a greater or less exhaus- 

 tion of the increased influence which formerly actuated the capillaries. 



3. Increase of the animal heat in an actively inflamed part. We have contended in 

 another place that animal heat is the result of the vital influence of the ganglial nerves 

 upon the vessels and the fluid circulating through them, and that the heat of the whole 

 body or of a single part has an intimate relation with the degree of Influence which this 

 system of nerves exerts, especially that part of it supplying the vessels, either as res- 

 pects the body generally, or as regards the part more particularly effected. If this po- 

 sition be granted, it cannot be denied that the augmented heat in inflammation is de- 

 rived from the same source, namely, the increased influence, on the vessels of the af- 

 fected part, of that particular system of nerves on which the production of animal 

 heat chiefly depends. (See the Note on the functions of the ganglionic system of nerves. ) 



From this it will be seen that, we consider inflammation, in its various forms and stages 

 to originate in, and to depend upon, the altered kind and degree of influence which 

 the ganglial system of nerves exerts on the capillaries of the part : that whenever this 

 influence is greater than natural, the action of the capillaries is greater than natural, 

 and whenever it is below the healthy condition, these vessels are equally deficient in a 

 requisite degree of action ; that the kind of influence is changed as well as the degree 

 of influence ; and that, as inflammation originates in this class of nerves, it may be con- 

 sidered as a lesion of the function of these nerves, and therefore occurring more fre- 

 quently in those tissues which are the least supplied with an additional and a compen- 

 sating influence from the other parts of the nervous system : hence the reason that in- 

 flammation is very seldom seen in the muscular fibre, to which the cerebral nerves are 

 so plentifully distributed, and hence the probable cause that it so frequently attacks 

 cellular parts, or those which are essentially cellular in their nature. 



At this place we have merely considered a few of the physiological relations of acute 

 inflammation, in a brief and an imperfect manner. The other points connected with 

 this subject which might be discussed, but which are more strictly pathological, are 

 1st, the different characters of acute inflammation, according to the textures in which 

 it is seated ; 2d, the stages of inflammation, in relation to the individual tissues, down 

 through their numerous grades until they reach the lowest ; 3d, inflammation in which 

 the influence bestowed on the vessels by the ganglial nerves is more or less exhausted 

 or destroyed ; 4th, the state of the venous capillaries and absorbents in the different 

 stages and grades of inflammation ; 5th, the varying phenomena which this species of 

 derangement presents according as it is modified by constitutional, peculiarities ; 6th, 

 the different manifestations of inflammation arising from the nature of its exciting 

 causes, Sec. These and other relations of this fundamental, and most important part of 

 pathology, will be considered in an extended manner on another occasion. 



