EFFECTS OF RESPIRATION ON THE AIR. 401 



can only be converted into water at the expense of oxygen derived from the 

 atmosphere. 



319. The fluid thrown off from the lungs is not pure water. It holds in 

 solution, as might have been expected, a considerable amount of Carbonic 

 acid, and also some animal matter, which, from the inquiries of Dr. R. A. 

 Smith, 1 would appear to be an albuminous substance in a state of decom- 

 position. A small quantity of Ammonia is usually, but perhaps not always, 

 thrown off.- It has been suggested that this, when present, may be derived 

 either from decomposing fragments of food or from carious teeth ; but Thiry 

 believed lie had demonstrated it in air expired to avoid contamination 

 through u ru::u!;i in t routed into the trachea of a rabbit. The test used 

 was Nessler's (solution of iodide of silver and iodide of potassium). Ran- 

 some estimates that an amount of Ammonia representing about 3 grains of 

 organic matter are eliminated by an adult man in twenty-four hours. Ac- 

 cording to Wiederhold, 3 the Chloride of Sodium and Ammonium, Uric 

 Acid and the U rates of Soda and Ammonia, may be detected in the expired 

 air. Ransome found a small quantity of Urea in one or two instances. If 

 the fluid be kept in a closed vessel, and be exposed to an elevated tempera- 

 ture, a very evident putrid odor is exhaled by it. Every one knows that 

 the breath itself has, occasionally in some persons, and constantly in others, 

 a fetid taint : when this does not proceed from carious teeth, ulceratious in 

 the air-passages, disease in the lungs, or other similar causes, it must result 

 from the excretion of the odorous matter, in "combination with watery vapor, 

 from the pulmonary surface. That this is the true account of it, seems evi- 

 dent from the analogous phenomenon of the excretion of turpentine, cam- 

 phor, alcohol, and other odorous substances, which have been introduced 

 into the venous system, either by natural absorption, or by direct injection ; 

 and also from the suddenness with which it often manifests itself, when the 

 digestive apparatus is slightly disordered, apparently in consequence of the 

 entrance of some malassimilated matter into the blood. Among the sub- 

 stances occasionally thrown off by the lungs, Phosphorus deserves a special 

 mention, on account of the peculiarity of the form under which it is elimi- 

 nated ; for it has been found that if phosphorus be mixed with oil, and be 

 injected into the bloodvessels, it partly escapes in an uuoxidized state from 

 the lungs, rendering the breath luminous. 4 And this luminous breath has 

 also been observed in spirit-drinkers, in whom the oxidation of the effete 

 matters of the system is impeded, in consequence of the demand set up by 

 the alcohol ingested for the oxygen introduced ( 311, vi). 



320. Not only exhalation, but also (under peculiar circumstances) absorp- 

 tion of fluid may take place through the Lungs. Thus Dr. Madden 5 has 

 shown that, if the vapor of hot water be inhaled for some time together, the 

 total loss by exhalation is so much less than usual, as to indicate that the 

 cutaneous transpiration is partly counterbalanced by pulmonary absorption ; 



1 Philosophical Magazine, vol. xxx, p. 478. 



2 See Richardson, The Cause of the Coagulation of the Blood, 1857, p. 360; Los- 

 fen, Zi-its. f. Biologic, Bd. i, p. 107; Thiry, Zeits. f. rat. Med., Bd. xvii, 1863, p. 

 166 ; Schenk, Pfliiger's Archiv, Bd. iii ; Kuhne and Strauch, Ontnilblatt, 1862. p. 

 578; Arthur Ransome, Journal of Anatomy and Physiology, 1870. vol. iv, p. 209; 

 Truchot, Comptes Rendus, 1873, t. ii, p. 11GO. Bachl, however (Zeits. f. Biologie, 

 Bd. v, p. 61), was unable to find any traces of it. 



3 Deutsche Klinik, 1858 Schenk states that a small quantity of ammonia is elimi- 

 nated by the lung? in the Rabbit, Guinea-pig, and Dog, but none by the skin. The 

 nature of the food has no influence on the quantity (Pfliiger's Archiv, Bd. iii, p. 

 470). 



4 Casper's Wochenschrift, 1849, Bd xv. 



5 Prize Essay on Cutaneous Absorption, p. 55. 



