6 PRACTICE OF PHYSIC. 



of inflammation ; or, if it be, that it is not merely by the ob- 

 struction that it produces ; as, among other reasons, I conclude 

 particularly from the following argument. 



7- Though an obstruction should be supposed to take place, 

 it will not be sufficient for producing the effects, and exhibiting 

 the phenomena that appear in inflammation. The theory that 

 has been commonly employed on this occasion is by no means 

 satisfying ; and, in fact, it appears from many observations and 

 experiments, that considerable obstructions may be formed and 

 may subsist, without producing the symptoms of inflammation. 



CCXLII. Obstruction, therefore, from a matter stopping up 

 the vessels (Gaub. Pathol. 284. 285.), is not to be considered as 

 the primary cause of inflammation; but, at the same time, it is suf- 

 ficiently probable, that some degree of obstruction does take 

 place in every case of inflammation. The distention, pain, red- 

 ness, and tumor, attending inflammation, are to be explained 

 only by supposing that the extremities of the arteries do not 

 readily transmit the usual quantity of blood impelled into them 

 by the increased action in the course of these vessels. Such an 

 obstruction may be supposed to happen in every case of an in- 

 creased impetus of the blood ; but it is probable, that, in the 

 case of inflammation, there is also a preternatural resistance to 

 the free passage of the fluids. " If obstruction occurs, it is not 

 as obstruction, or from intercepting the passage of such a quan- 

 tity of blood, that it has its effects; but it is attended with some 

 degree of tension, which necessarily proves a stimulus to the 

 neighbouring vessels, and at length to the whole system." 



CCXLIII. From the doctrine of fever, we are led to be- 

 lieve, that an increased action of the heart and arteries is not 

 supported, for any length of time, by any other means than a 

 spasm affecting the extreme vessels ; and that the same spasm 

 takes place in inflammation seems likely, because that every 

 considerable inflammation is introduced by a cold stage, and is 

 accompanied with that and other circumstances of pyrexia. It 

 seems also probable, that something analogous to this occurs 

 even in the case of those inflammations which appear less con- 

 siderable, and to be purely topical. 



CCXLIV. From all this, the nature of inflammation may, in 

 many cases, be explained in the following manner. Some causes 



