THE BLOOD. 89 



those vessels This condition of the vessels is always ac- 

 companied by certain structural alterations, which affect not 

 merely the corpuscles themselves, but also the vessels and 

 parts adjacent to them ; these alterations being merely at- 

 tributable to the impediment presented to the onward pro- 

 gress of the blood in the capillaries by the accumulation in 

 them of the blood corpuscles. 



We now know that the proximate cause of inflammation 

 consists in an abnormal accumulation of the corpuscles of the 

 blood in the minute capillary vessels, and which accumulation 

 we perceive must inevitably impede the function of the part 

 in which the vessels are thus surcharged, alter its structure, 

 and finally tend to a sympathetic disturbance of the entire 

 economy. For this discovery we are indebted to the mi- 

 croscope. It will thus be seen that some of the ancient 

 hypotheses in reference to the proximate cause of inflamma- 

 tion were not so very far wrong, and that most of them 

 recognise the fact that it is the capillary vessels and blood 

 corpuscles which are mainly concerned in the production of 

 the phenomena of inflammation. 



Finally, inflammation may, like congestion, terminate in 

 resolution ; but, unlike congestion, it always leaves per- 

 manent traces of its visitation, the resolution being but in- 

 complete. It may terminate, also, in " hepatization," or in 

 " purulent infiltration." The fibrin of the blood is the chief 

 agent in producing the consolidation of the structure known 

 by the term hepatization, while it is the white corpuscles 

 analogous to those of the blood, as will be seen hereafter, 

 that give rise to the purulent formation. 



PATHOLOGY OF THE BLOOD. 



We come now to the consideration of the most important 

 division of our Chapter upon the blood, viz. that which treats 

 of the pathological changes which that fluid undergoes, and 

 a full and clear understanding of which is so necessary to the 

 safe and successful treatment of disease. 



These pathological alterations are numerous, and engage 



