4 INFLAMMATION. 



unable to convey it away ; it accumulates in the part, forming 

 the inflammatory exudate. 



Eeasoning upon the foregoing, one is tempted to conclude 

 that inflammation is characterised by an increased nutrition of 

 the part ; but such is not the case. During all the processes 

 of inflammation there is no such thing as an increased forma- 

 tion of the natural structures of the inflamed part — they are 

 not even maintained; and it is only after the inflamma- 

 tion has subsided that there is an increased formation of 

 some of the tissues, as the areolar, the bony, and the horny 

 structures. 



Whilst the inflamed structure itself suffers deterioration, the 

 process of inflammation is, however, characterised by a produc- 

 tion of lowly organized material. 



Having now endeavoured to show what I conceive to be the 

 essential nature of inflammation, viz., a perverted nutrition, con- 

 sequent on injurious irritation of tissues, I shall call attention 

 to the series of experiments that have been made to demonstrate 

 the 



PHENOMENA OF INFLAMMATION. 



The latest observers state that the microscopically visible 

 changes that occur in a transparent vascular membrane of 

 an animal, such as the web of the frog's foot, differ con- 

 siderably, according to the irritant employed. A weak solution 

 of caustic soda, dilute sulphuric acid, &c., produce dilatation, flrst 

 of the arteries, and subsequently of the capillaries, with marked 

 acceleration of the circulation, followed by arterial contraction 

 and capillary anaemia. But liquor ammonise, and carbonate of 

 ammonia in substance, appear always to occasion a certain de- 

 gree of primary arterial contraction, which begins in one or two 

 minutes after excitation, and is attended with retarded flow 

 jf blood through the capillaries ; distension of the branches 

 given otf by the artery nearer the heart, and increased activity 

 of circulation in the neighbourhood of the irritated part. This 

 state of things lasts for an hour or two, and is succeeded by 

 dilatation and acceleration. Croton oil appears to occupy an 

 intermediate position between the first-named stimulants and 

 ammonia; for while it always gives rise to acceleration of 

 the flow of blood as a primary result, this change is some- 



