1 82 On vegetable Poisons, 



of the brain, it may, in some instances at least, be made t« 

 recover, if respiration is artificially produced, and continued 

 for a certain length of time. 



From analogy we might draw some conclusions respect- 

 ing the mode in which some other vegetable poisons pro- 

 duce their effects on the animal system; but I forbear to 

 enter into any speculative inquiries; as it is mv wish, in the 

 present communication, to record such facts only, as appear 

 to be established by actual experiment. 



Addition to the Croonian Lecture for the Year 1810. 



In the experiments formerly detailed, where the circula- 

 tion was maintained by means of artificial respiration after 

 the head was removed, I observed that the blood, in its 

 passage through the lungs, was altered from a dark to a 

 scarlet colour, and hence T was led to conclude that the 

 action of the air produced in it changes analogous to those 

 which occur under ordinary circumstances. 1 have lately, 

 with the assistance of my friend Mr. W. Brande, made the 

 following experiment, which appears to confirm the truth 

 of this conclusion. 



An eliistic gum bottle, having a tube and stop-cock con- 

 nected with it, was filled with about a pint of oxygen gas. 

 The spinal marrow was divided in the neck of a young rab- 

 bit, and the blood-vessels having been secured, the head 

 was removed, and the circulation was maintained by in- 

 fla'ing the lungs with atmospheric air for five minutes, at 

 the end of which time the tube of the gum bottle was in-f 

 serted into the trachea, and carefully secured by a ligature, 

 so that no air might escape. By making pressure on the 

 gum bottle, the gas was made to pass and repass into and 

 from the lungs about thirty limes in a minute. At first, 

 the heart acted one hundred and twenty times in a minute, 

 with regularity and strength ; the thermometer, in the rec- 

 tum, rose to 100°. At the end of an hour, the heart acted 

 as frequently as before, but more feebly; the blood in the 

 arteries was very little more florid than th?t in the veins j 

 the thermometer in the rectum had fallen to 93^. The gum 

 bottle was then removed. On causinti; a stream of the gas 

 which it contained to pass through lime-water, the pre- 

 sence of carbonic acid was indicated by the liquid being 

 instantly rendered turbid. The proportion of carbonic acid 

 was not accmately determined ; but it appeared to forni 

 aboiit one-hall of the quantity of gas in the bottle. 



B. C. Brodie. 



XXXV. An 



