Proceedings of the British Association. 127 



Some writers look on it in every instance as the result of inflammation ; 

 slight modifications of vitality may permit its occurrence during life, as 

 we find it, where chronic inflammation has existed, giving rise to depo- 

 sits of an atheromatous matter. When dependent on inflammation it 

 will be found affecting the inner coat only, but when on other causes it 

 will often pervade the elastic or middle coat as well as the serous. Fi- 

 nally, he stated that it might be found depending on the co-existence of 

 those causes which were capable of producing it singly. 



Mr. Hodgson repeated the statements which he made after the read- 

 ing of Dr. Macartney's paper, on Tuesday ; that, although nature does 

 sometimes use other means for suppressing haemorrhage, the most fre- 

 quent mode was a vital constriction and contraction of the coats of the 

 artery, and that this constriction and narrowing of the arterial tube may 

 be produced by exposure and by pressure. That this is the mode adop- 

 ted to prevent the haemorrhage in cases of Gangrene, when separation 

 is effected. In support of these views, he presented to the Section some 

 preparations and drawings, particularly illustrating the various condi- 

 tions in which arteries are found, after successful operations for aneu- 

 rism : true anuerism, he pointed out as depending on a weakening and 

 degeneration of the middle coat of the artery. 



Dr. Macartney thought that it was of importance to discriminate be- 

 tween the red appearances described by Mr. Hodgson and inflamma- 

 tion ; they had a painted appearance, were devoid of tumefaction, and 

 were most perfectly distinguished by being insusceptible of injection. 

 There was, he stated, much analogy in the red patches observed on the 

 pharynx and oesophagus in cases of hydrophobia ; he remarked that 

 these appearances might not depend on the putrefactive process, but be 

 caused more by changes in the blood itself than in the solids. Dr. Ma- 

 cartney dwelt on the important part played by the effusion of coagula- 

 ble lymph in the closure of arteries, independent of and even previous 

 to inflammation. 



Mr. C. T. Coathupe detailed the results of a series of experiments on 

 the Respiration of Deteriorated Atmospheres, which he instituted to 

 determine whether the injurious effects which have followed the respira- 

 tion of charcoal vapours had depended on carbonic acid, as was gene- 

 rally thought, or on the specific agency of some other volatile product. 

 The volatile products of the combination of charcoal he stated to be as 

 follows : — 



Carbonate of Ammonia, 

 Hydrochlorate of Ammonia, 

 Sulphate of Ammonia, 

 Volatile Empyreumatic Oil, 

 Carbonic Acid Gas, 

 Carbonic Oxide, 

 Oxygen, 

 Nitrogen, 

 Aqueous Vapour. 



