BY DR. KLEIN. 169 



CHAPTER XIV. 



(APPENDIX.) 

 STUDY OF INFLAMED TISSUES. 



Inflammation of Epithelium. The inflammatory 

 changes of the epithelial elements of the cornea may be 

 studied by abrading the epithelium over a limited surface in 

 several frogs, and examining the organ at various periods after 

 the injury. The cornea must be studied in the fresh state 

 (with and without irrigation with serum), as well as after pre- 

 paration with gold and hardening in alcohol. Sections in both 

 directions must be made of the preparations so obtained. 

 Evidence is thus obtained (1) of the division of the nuclei of 

 the epithelial cells, (2) of the overgrowth of the bodies of the 

 cells, and (3) of their subsequent division. 



The examination of the catarrhal secretions of any inflamed 

 mucous membrane which is covered with pavement epithelium, 

 is very instructive. If a small drop taken from the surface of 

 such a membrane is examined, either without any addition, or 

 diluted with a drop of serum, it is seen that among a great 

 number of amoeboid young cells (pus cells) a few larger struc- 

 tures are to be found, consisting of granular protoplasm, 

 which, as regards their form and size, and the characters of 

 their nuclei, resemble epithelial cells. Some of them contain 

 vacuoles of very various size, each exhibiting in its wall a well- 

 defined nucleus, which either shows constrictions or is already 

 divided. In those vacuoles which are largest there are pus- 

 corpuscles. Besides these, thin-walled vesicular bodies are 

 seen, of great size, filled with pus-corpuscles ; and between 

 them and the cells containing vacuoles there are all transitions. 

 If vertical sections are made of a bit of the inflamed mucous 

 membrane after treatment with gold, it is learnt that these 

 structures correspond to the cells of the superficial layers. In 

 fresh preparations taken in such a way as to include the ele- 

 ments of deeper layers, large epithelial cells are seen which 

 exhibit very distinct indications of division both in their 

 bodies and nuclei. On the warm stage these cells may be 

 seen actually dividing. To obtain permanent preparations, 

 the fresh inflamed mucous membrane must be placed in two 

 per cent, solution of bichromate of potash. After two or 

 three days, sections may be made by shaving off a portion of 



