EFFECTS OF SUSPENSION OR DEFICIENCY OF RESPIRATION. 535 



Cyanogen is another gas which has an actively-poisonous influence upon 

 animals, when absorbed into the lungs ; its agency, also, is of a narcotic 

 character. 



573. It is singular that the effects of the respiration of pure Oxygen should 

 not be dissimilar. At first, the rapidity of the pulse and the number of the 

 respirations are increased, and the animal appears to suffer little or no incon- 

 venience for an hour ; but symptoms of coma then gradually develop themselves, 

 and death ensues in six, ten, or twelve hours. If the animals are removed into 

 the air before the insensibility is complete, they then quickly recover. When the 

 body is examined, the heart is seen beating strongly, while the diaphragm is 

 motionless; the whole blood in the veins, as well as in the arteries, is of a bright 

 scarlet color ; and several of the membranous surfaces have the same tint. The 

 blood is observed to coagulate with remarkable rapidity ; and it is to the altera- 

 tion in its properties, occasioned by hyper-arterialization, and indicated by this 

 condition, that we are probably to attribute the fatal result. There can be no 

 doubt that in this instance, an undue amount of oxygen is absorbed ; and it does 

 not seem unlikely that one cause of the fatal result, is a stagnation of the blood 

 in the systemic capillaries, consequent upon the want of sufficient change in its 

 passage through them. When Nitrogen or Hydrogen is breathed for any length 

 of time, death results from the deprivation of Oxygen, rather than from any 

 deleterious influence which these gases themselves exert. Death is also caused 

 by the inhalation of several gases of an irritant character, such as Sulphurous, 

 Nitrous, and Muriatic acids ; but it is doubtful how far they are absorbed, or 

 how far their injurious effects are due to the abnormal action which they excite 

 in the lining membrane of the air-cells and tubes. It cannot be doubted, that 

 Miasmata and other morbific agents diffused through the atmosphere, are more 

 readily introduced into the system through the pulmonary surface than by any 

 other; and our aim should, therefore, be directed to the discovery of some coun- 

 teracting agents, which can be introduced in the same manner. The Pulmonary 

 surface affords a most advantageous channel for the introduction of certain medi- 

 cines that can be raised in vapor, when it is desired to affect the system with 

 them speedily and powerfully ; such is pre-eminently the case with those Anaes- 

 thetic agents, ether and chloroform, whose introduction into the various depart- 

 ments of Medical and Surgical practice constitutes a most important era in the 

 history of the healing art ; also with Mercury, 1 Iodine, Tobacco, Stramonium, 

 &c. 



3. Effects of Suspension or Deficiency of Respiration. 



574. We have now to consider the results of the cessation of the Respiratory 

 function, and the consequent retention of Carbonic Acid in the blood. If this 

 be sufficiently prolonged, a condition ensues, to which the name of Asphyxia 

 has been given ; the essential character of which is the cessation of muscular 

 movement, and shortly afterwards of the circulation; with an accumulation of 

 blood in the venous system. The time which is necessary for life to be de- 

 stroyed by Asphyxia varies much, not only in different animals, but in different 

 states of the same. Thus, warm-blooded animals are much sooner asphyxiated 

 than Reptiles or Invertebrata; on the other hand, a hybernating Mammal sup- 

 free in the combustion of charcoal, besides carbonic acid. Mr. Coathupe (loc. cit. ) states 

 these to be Carbonate, Muriate, and Sulphate of Ammonia, Carbonic Oxide, Oxygen, 

 Nitrogen, Watery vapor, and Einpyreumatic Oil : to these Sulphurous acid may appear to 

 be properly added. 



1 The beneficial results of the introduction of Mercury by inhalation are strikingly set 

 forth in Mr. Langston Parker's Essay on "The Treatment of Secondary, Constitutional, 

 and Confirmed Syphilis." 



