60 INFLAMMATION. 



'' The cause of obstruction/' says this learned writer, " is 

 spasm of the extreme arteries supporting an increased action 

 in the course of them/' So far as distension or swelUng 

 is concerned, spasm is a condition quite opposed to this, 

 which would indicate that less instead of more blood existed 

 in the inflamed part. In framing theories on inflammation, 

 the grand difficulty has been found in reconciling the in- 

 creased action of the vessels with a state of preternatural 

 distension of them. The more a vessel is distended, the 

 more we believe its contractile power to be weakened ; so 

 that we are not only giving the vessels more to perform, but 

 in supposing them to be dilated, we are placing them, in cir- 

 cumstances the very opposite of those most favorable to 

 exertion. Then, whether the capillaries possess a power of 

 propelling the blood_, or whether it is forced through them 

 by the heart; or whether the two powers conjoin in circu- 

 lating the blood, we are by no means certain. 



These considerations present difficulties which, when 

 added to the universal influence of the nervous system, con- 

 tribute greatly to confuse any investigation into the nature 

 of inflammation. Of late years the subject, however, has 

 undergone renewed inquiry, and much assistance has been 

 gained by a more accurate observation of parts actually 

 under disease ; and the result has been, the pretty general 

 admission of certain facts on which future theories may be 

 safely grounded. 



That an increased Quantity of Blood is sent to an 

 INFLAMED Part, admits of demonstration : First, from the 

 throbbing of the arterial trunks supplying it, which is an 

 unequivocal sign of increased action ; secondly, from the 

 state of the part itself; viz., its redness ; the distension of 

 its vessels; their dilatation or enlargement; the admission 

 of red blood into vessels which were of insufficient calibre 

 to admit any but the serous part of that fluid. 



That the Blood in the inflamed Part is not accu- 

 mulative, CONGESTIVE, OR STAGNANT, BUT IN CONTINUAL 



ACTIVE Circulation through it, is demonstrated by the 

 distended and enlarged state of the veins which convey it 



