204 PROCEEDINGS OF SOCIETIES. 



arm, avoiding all blood-vessels, so as to prevent blood corpuscles 

 getting on to the mesentery, then di'aw out the intestine, and 

 having placed the mesentery on the cork plate moisten its surface 

 with salt solution. It is best to expose the mesentery for three 

 hours before the observation be made, and a large vessel is best for 

 examination. The chief difficulties which may be experienced are 

 (ff) imperfect curarization, (b) adhesions, or (c) tearing the 

 mesentery. 



The mesenteries of warm-blooded animals had been used by 

 Strieker on his large warm stage, but Dr. Bruce had no experience 

 with them himself, and their examination was attended with a good 

 deal of difficulty. 



The tongue of the frog is useful for studying inflammation. 

 Cohnheim first used it, placing the frog on its back and observing 

 the dorsum of the tongue, in which he excited inflammation by 

 snipping the mucous membrane ; caustic has also been used for 

 this purpose. Cutting the mucous membrane, however, gives rise 

 to haemorrhage, therefore Cohnheim prefers making use of the 

 under surface, in which he causes inflammation by passing a ligature 

 round the root of the tongue. At the end of forty-eight hours he 

 undoes this and then white blood-corpuscles are seen to be passing 

 freely through the vessels. Dr. Bruce has found, however, that 

 after ligature the circulation does not always recover. To prevent 

 the ligature injuring the tongue it is best to place a piece of leather 

 between the ligature and the tongue. Dr. Bruce also referred to 

 the tail of the tadpole, the wing of the bat, and the cornea of the 

 rabbit, &c., as structures in which inflammation may be observed ; 

 and then concluded by asking an opinion as to the origin of pus, 

 whether the members held with Cohnheim, that all pus comes from 

 the vessels, or from the connective tissue corpuscles, or from both 

 sources. 



The President stated his opinion that investigating living tissues 

 would probably be the only means of advance in pathological 

 research. Paget even gave but crude information on inflammation, 

 while Cohnheim has elucidated much in living tissues. 



Dr. Payne referred to the difficulty of Cohnheim's experiment on 

 the mesentery. He also thought that Virchow's idea of the 

 origin of pus, though now old-fashioned, was far from being over- 

 turned by Cohnheim, and that in inflammation of mucous surfaces 

 we see instances of small cells in larger (mother) ones, though he 

 acknowledged it might be true that the small cells migrated into 

 the larger. In the cornea and omentum proliferation has been seen. 

 One view may be taken of all these structures, viz. that some parts of 

 the body, and especially those of embryonic character show greater 

 tendency to reproduction than others. He had heard Virchow state his 

 conviction that the more perfect endothelium of the peritoneum cou'd 

 not go on producing otlier elements wliile the more simple endothe- 

 lium of the lymphatics might do so. Dr. Payne then stated that 

 at present only a small class of tissues bad been studied in a living 

 and inflamed condition, and until all tissues have been examined it 



