EFFECTS OF SUSPENSION OR DEFICIENCY OF RESPIRATION. 407 



by renewing its appropriate stimulus of arterial blood. 1 Hence, if the stop- 

 page of the circulation have not been of too long continuance, it may be re- 

 newed bv artificial respiration ; 2 for the replacement of the carbonic iicid by 

 oxygen in the air-cells of the lungs, restores the circulation through the pul- 

 monary capillaries; and thus at the same time relieves the distension of the 

 right ventricle, and conveys to the left the due stimulus to its actions. Of 

 the mode in which the pulmonary circulation is thus stagnated by the want 

 of oxygen, and renewed by its ingress into the lungs, no other consistent ex- 

 planation can be given, than that which is based on the doctrine already 

 laid down in regard to the capillary circulation in general ( 269) ; namely, 

 that the performance of the normal reaction between the blood and the sur- 

 rounding medium (whether this be air, water, or solid organized tissue) is a 

 condition necessary to the regular movement of the blood through the ex- 

 treme vessels. That no mechanical impediment to its passage is created (as 

 some have maintained) by the want of distension of the lungs, has been fully 

 proved by the experiments of Dr. J. Reid on the induction of Asphyxia by 

 the respiration of nitrogen ; at the same time it must be admitted that the 

 contraction of the smaller arteries is a very important factor in the arrest of 

 the circulation in the-pulmouary capillaries of the lungs, since it is in accord- 

 ance with what is elsewhere seen when the vaso-motor centres are stimulated, 

 and is very certainly deducible from the phenomena of pressure observed in 

 the arteries and veins respectively. 3 



325. It is obvious that by the repeated passage of the same air through 

 the lungs, it must, though originally pure and wholesome, become so strongly 

 impregnated with carbonic acid, and must lose so much of its oxygen, as to 

 be rendered utterly unfit for the continued maintenance of the aerating pro- 

 cess; so that the individual who continues to respire it, shortly becomes 

 asphyxiated. There are several well-known cases, in which the speedy 

 death of a number of persons confined together has resulted from neglect of 

 the most ordinary precaution for supplying them with air. That of the 

 " Black Hole of Calcutta," which occurred in 1756, has acquired an un- 

 enviable pre-eminence, owing to the very large proportion of the prisoners 

 123 out of 146 who died during one night's confinement in a room 18 feet 

 square, only provided with two small windows ; and it is a remarkable con- 

 firmation of the views formerly stated ( 223), and presently to be again ad- 

 verted to, that of the 23 who were found alive in the morning, many were 

 subsequently cut off by " putrid fever." Such catastrophes have occurred 

 even in this country, from time to time, though usually upon a smaller 



1 Setschenow has made some important researches on the amount and kind of gases 

 contained in the blood of asphyxiated animals (dogs). He found that only traces of 

 oxygen could be discovered in either the venous or arterial blood : the quantity -of 

 nitrogen varied from 1 to "1 parts, of free carbonic acid from 28 to 38.8 parts, and 

 of combined carbonic acid from 1.7 to 4 parts. (Henle and Meissner, Bericht, 1859, 

 p. 305.) 



2 Of the two chief modes of performing this operation, Dr. Silvester's method of 

 alternately raising and depressing the arms, 15 or 16 times in the minute, of which 

 Dr. Bains's is only a modification, appears to be far preferable to Dr. Marshall Hall's 

 method of rotating the body half over, and pressing on its chest. See Marshall 

 Hall's work on Drowning, Med. Times and Gaz., 1858, vol. i, pp. 147, 176 et seq., 

 and Med.-Chir. Transact., vol. liii, 1870, p. 291. 



3 For a fuller discussion of the pathology of Asphyxia, see the Cyclop, of Anat. and 

 Phys., art. Asphyxia, by Prof. Alison; the Library of Practical Medicine, vol. iii, 

 art. Asphyxia, by the Author ; Experimental Essays, by Dr. J. Reid, On the Order 

 of Succession in which the Vital Actions are arrested in Asphyxia, in the Eclinb. 

 Med. and Surg. Journ., 1841, and in his Anat., Physiol., and Pathol. Researches ; 

 and the Experimental Inquiry by Mr. Erichscn, in the Eclinb. Med. and Surg. 

 Journ., 1845. 



