SENSE OF SUFFOCATION. 4:85 



ratoiy movements are a little restricted under the influence 

 of depressing emotions, an involuntary deep or sighing in- 

 spiration is made, for the purpose of changing the air in the 

 lungs more completely. The increased consumption of oxygen 

 and a certain amount of interference with the mechanical 

 process of respiration during violent muscular exercise put 

 us " out of breath ;" and for a time the respiratory move- 

 ments are exaggerated. This is perhaps the first physiological 

 way in which the want of air is appreciated by the senses. 

 A deficiency in hematosis. either from a vitiated atmosphere, 

 mechanical obstruction in the air-passages, or grave trouble 

 in the general circulation, produces all grades of sensations, 

 from the slight oppression which is felt in a crowded room, 

 to the intense distress of suffocation. When hematosis is but 

 slightly interfered with, only an indefinite sense of oppression 

 is experienced ; the respiratory movements are a little in- 

 creased, the most marked effect being an increase in the 

 number and extent of sighing inspirations. In the experi- 

 ments upon animals to which we have referred, when artifi- 

 cial respiration was interrupted, we first noticed regular and 

 not violent contractions of the respiratory muscles ; but as the 

 sense of want of air increased, every muscle which could be 

 used to raise the chest was brought into action. In the 

 human subject in this condition, the countenance has a 

 peculiar expression of anxiety and distress, and the move- 

 ments soon extend to the entire muscular system, resulting 

 in general convulsions, and, finally, insensibility. 



Bearing in mind the fact, that though these sensations 

 are referred to the lungs, indicating increased respiratory 

 effort as the common means for their relief, they have their 

 real point of departure in the general system, we can under- 

 stand the operation of various abnormal conditions of the 

 circulation, when the lungs are adequately supplied with 

 fresh air. The first subjective symptom of air in the veins 

 is a sense of impending suffocation. There is no want of air 

 in the lungs, but the circulation is instantaneously inter- 



