RESPIRATION. 



Seguin. 8 Dr. Edwards has found less evolved in summer than in 

 winter.* 



Dr. Prout and Dr. Fyfe u have found the quantity of carbonic 

 acid gas diminished by mercury, nitric acid, vegetable diet, tea, 

 substances containing alcohol, depressing passions, long fasting, 

 and fatigue, and probably by sleep. Dr. Prout found that it 

 undergoes in himself an increase from daybreak till noon, and a 

 tlecrease from noon till sunset, remaining at the minimum till 

 daybreak. In the experiments of Allen and Pepys, the formation 

 of carbonic acid gas slackened when the guinea-pigs fell asleep. 

 Dr. Prout also observed that an increase or decrease from the 

 maximum or minimum was followed by a proportional decrease or 

 increase during a diurnal period. It would appear, also, that less 

 is formed in infancy, and more as the adult age is approached, in 

 brutes.* 



When the air is not changed, death in general occurs long be- 

 fore all the oxygen is consumed, through the carbonic acid which 

 is formed; but bees, some worms and mollusca, completely deoxi- 

 dize it. x Snails will live in air in which a bird has died. 



Lavoisier removed the carbonic acid by potash as guickly as it 

 was produced, and found that a guinea-pig could live in air con- 

 taining but 6*66 per cent, of oxygen, and with still less became 

 only drowsy . y 



8 Memoires de VAcadtmie des Sciences. 1789. p. 575. 



'* 1. c. p. 200. sqq. 



u 1. c. Dissert. Inaugur. fyc. Edin. 1814. The smallest quantity yet observed 

 was in a diabetic patient of mine, taking very large doses of opium and nux 

 vomica. Numerous Cases, illustrative of the Efficacy of the Hydrocyanic or Prussic 

 Acid in Affections of the Stomachy with a Report upon its Powers in Pectoral and 

 -other Diseases, in which it has been already recommended, and some Facts respecting 

 the Necessity of varying the Doses of Medicines according to circumstances, and the 

 Use of Opium in Diabetes. By John Elliotson, M. D. &c. p. 99. 



v Boyle, Works, vol. iii. p. 360. Edwards, 1. c. p. 189. sqq. 



x Vauquelin, Annales de Chimie, torn. xii. p, 278. Spallanzani, Mem, sur la 

 Respiration, p. 63. 



y Some assert that the respiration of pure oxygen excites violently, others gently, 

 others not at all ; some, that more oxygen is consumed than in common, some no 

 more. Mr. Broughton, in a paper read a few years ago in the Royal Society, but 

 not published, found, as Allen and Pepys had previously, that oxygen, when 

 respired pure, excites and causes all the visible blood to be florid; but the animal 

 gradually becomes exhausted, falls in temperature, and at length dies, while the 

 oxygen is still pure enough to produce the same effects on a second and third ani- 

 mal. The blood quickly coagulates after the respiration of pure oxygen. Pure 



Q 2 



