2 INFLAMMATION. 



living tissue when it is injured, provided tliat the injury is not 

 of such degree as at once to destroy its structure and vitality." 



If I were to attempt to give a definition of inflammation, I 

 would say that it is a perverted nutrition of a living part, the 

 elfect of irritation or injury. 



rATIIOLOGY. 



If a non-vascular structure — the cornea, for example — he 

 excised in the following manner, as recommended by Professor 

 von Eecklinghausen, changes which are identical with the 

 earliest of the inflammatory process may be observed. 



" The anterior chamber is first punctured so as to let out a 

 drop of aqueous humour, which is placed on the object-glass ; 

 the cornea is then excised and placed in the drop with Desce- 

 met's membrane uppermost. The preparation thus obtained is 

 examined without a cover-glass, in a closed chamber in which 

 the air is saturated with moisture, so that no evaporation can 

 take place, and consequently no alteration in the density of the 

 liquid in which the cornea is immersed. The healthy cornea 

 is absolutely transparent, and when it is examined under the 

 microscope, in the manner described, no structure can be dis- 

 tinguished. This homogeneity, so essential to the function of 

 the cornea, is a condition inseparable from life; if the observa- 

 tion is continued till the tissue begins to die, its structural 

 elements gradually come into view — first the epithelia, then 

 the lymphoid elements proper to the tissue, then the cornea 

 corpuscles. The explanation of the fact is, that whereas in life 

 the elements of which the cornea is formed affect light exactly 

 in the same degree, their respective refractive powers are slightly 

 altered in the act of dying. 



" If a cornea is examined in the same way, which has been 

 irritated a quarter of an hour before by the application of a 

 point of caustic to its surface, the conjunctival epithelial layer 

 can at once be distinguished, along with a few leucocytes, 

 underneath and among the epithelial elements. If an hour or 

 two has elapsed, the proper cornea corpuscles are visible, as 

 dark stellate or spindle-shaped spots on a transparent ground. 

 Of these some are homogeneous, and can be distinguished from 

 the surrounding substance bv a slinht difference of shade. In 



