402 OF RESPIRATION. 



the pulmonary exhalation being at the same time entirely checked. It is 

 probable that, if the quantity of fluid in the blood had been previously di- 

 minished by excessive sweating, or by other copious fluid secretions, the pul- 

 monary absorption would have been much greater. Still in the cases for- 

 merly mentioned ( 146), in which a large increase in weight could only be 

 accounted for on the supposition of absorption of water from the atmosphere, 

 it seems probable that the cutaneous surface was chiefly concerned; for it 

 can only be when the air introduced into the lungs is saturated with watery 

 vapor, that the usual exhalation will be checked, or that any absorption can 

 take place. 



321. That absorption of other volatile matters diffused through the air, 

 however, is continually taking place by the Lungs, is easily demonstrated. 

 A familiar example is the effect of the inhalation of the vapor of Turpen- 

 tine upon the urinary excretion. It can only be in this manner that those 

 gases act upon the system, which have a noxious or poisonous effect wheu 

 mingled in small quantities in the atmosphere ; and it is most astonishing to 

 witness the extraordinary increase in potency which many substances ex- 

 hibit, when they are brought into relation with the blood in the gaseous 

 form. The most remarkable example of this kind is afforded by Arseniu- 

 retted Hydrogen, the inspiration of a few hundredths of a grain of which has 

 been productive of fatal consequences, the resulting symptoms being those of 

 arsenical poisoning. Next to this, perhaps, in deleterious activity, is Sul- 

 phuretted Hydrogen ; but it would seem that the effects of this gas upon the 

 Human subject are scarcely so violent as they are upon animals ; for though 

 it has been found that the presence of ^go^ n P ar ^ f ^ ^ n tne respired air 

 will destroy a bird in a very short time, that -g-ooth part suffices to kill a 

 dog, and that ^g^th part is fatal to a horse, yet M. Parent-Duchatelet has 

 affirmed that workmen habitually breathe with impunity an atmosphere 

 containing one per cent., and that he himself has respired, without serious 

 symptoms ensuing, air which contained three per cent. There can be no 

 doubt, however, that the continued inhalation of air thus contaminated would 

 be speedily fatal. Sulphuretted hydrogen and Hydrosulphuret of ammonia 

 are given off from most forms of decaying animal and vegetable matter ; and 

 it is undoubtedly to the accumulation of these gases, that the fatal results 

 which sometimes ensue from entering sewers are to be chiefly attributed. 

 Antimoniuretted and Phosphuretted hydrogen may also be included with 

 the above as poisonous gases. These all oxidize themselves at the expense 

 of the oxygen of the blood, 1 and as a result of this appropriation, induce 

 dyspnoea, convulsions, and asphyxia. Other poisonous gases, as Carbonic 

 oxide, 2 Deutoxide of Nitrogen, and Cyanuretted hydrogen, according to 

 Hermann, 3 form a group that displace the oxygen and enter into combina- 

 tion with the haemoglobin, producing a clear red solution, and inducing the 

 same symptoms as the former. Deutoxide of Nitrogen is, however, properly 

 included under the irrespirable gases. Other poisonous gases again, as Pro- 

 toxide of Nitrogen, Olefiant gas, Chloroform, and Carbonic acid, are intoxi- 

 cating in their properties, affecting the functions of the brain, and ultimately 

 producing a narcotic effect. Amongst the irrespirable gases which, unless 

 exceedingly diluted, induce spasm of the glottis, may be enumerated Car- 



the experiments of Kaufrmum and Rosen tlnil on the action of Sulphuretted 

 Hydrogen, in Reiehert's Arohiv, 18(55, Heft vi ; those of Hoppe-Seyler on the same, 

 and on Antimoniuretted and Arseniuretted Hydrogen, Med. Chem. Unters., Ileft i, 

 p. 133, and those of Dybkowsky on Phosphuretted Hydrogen. 



-' See Tranbe, Gurlt's Vcrhand. d. Berlin. Uesellsch., 1806, p. G7, and C. Bernard, 

 Rev. Scientif., t. vi, 1870; and Lemons sur les Amesthesiques. 



3 Physiologic, 1874, pp. 45 and 101. 



