438 ANATOMICAL AND PATHOLOGICAL OBSEEVATIONS. 



vascular fringes. They are situated where they cannot inter- 

 fere with the motions of the joint. They hang into those 

 jiarts of the cavity best fitted for containing and acting as 

 reservoirs of synovia ; and their high vascularity, and the 

 pulpy nature of their serous covering, tend to strengthen this 

 opinion. 



The phenomena attending inflammatory action of the 

 membranes are highly interesting. The capillaries are all on 

 one side of the membrane, and yet the serum and lymph are 

 on the other. The capillary vessels in healthy action have 

 no power in themselves of throwing out any of their contents. 

 They do not secrete in virtue of any power inherent in them- 

 selves. Do they acquire this power during inflammation ? 

 Or will any of the hypotheses of effusion account for the 

 lymph and serum being on the free surface of the serous 

 membranes, and so little, if any, in the subserous textures ? 



I do not see how we can, in the present state of the 

 science, account for phenomena of this kind by referring 

 them to actions of the extreme vessels. We must look for 

 an explanation, I am inclined to believe, in a disturbance of 

 the forces which naturally exist in the extravascular portions 

 of the inflamed part. * 



* "The i>rimary change," in inflammation, "is in the vital affinities, 

 common to the solids and fluids, and acting chiefly in that part of the system 

 where the solids and fluids are most intimately mixed, and are continually 

 interchanging particles." — Alison's Outlines of Physiology aiid Pathology, page 

 437. 



