TIESPIKATIOK. 293 



correspond with the stages of the condition which are usually recog- 

 nized, these are (1), the stage of exaggerated breathing; (2), the stage 

 of convulsions; (3), the stage of exhaustion. 



In the first stage the breathing becomes more rapid and at the same 

 time more deep than usual, the inspirations at first being especially ex- 

 aggerated and prolonged. The muscles of extraordinary inspiration are 

 called into action, and the effort to respire is labored and painful. This 

 is soon followed by a similar increase in the expiratory efforts, which 

 become excessively prolonged, being aided by all the muscles .of extra- 

 ordinary expiration. During this stage, which lasts a varying time, 

 from a minute upward, according as the deprivation of oxygen is sudden 

 or gradual, the lips become blue, the eyes are prominent, and the ex- 

 pression intensely anxious. The prolonged respirations are accompanied 

 by a distinctly audible sound; the muscles attached to the chest stand 

 out as distinct cords. This stage includes the two conditions hyperpnoea 

 and dyspnoea already spoken of. It is due to the increasingly powerful 

 stimulation of the respiratory centres by the increasingly venous blood. 



In the second stage, which is not marked out by any distinct line of 

 demarcation from the first, the violent expiratory efforts become con- 

 vulsive, and then give way, in men and other warm-blooded animals at 

 any rate, to general convulsions, which arise from the further stimula- 

 tion of the centres. The spasms of the muscles of the body in general 

 occur, and not of the respiratory muscles only. The convulsive stage 

 is a short one, and lasts far less than a minute. 



The third stage or stage of exhaustion. In it, the respirations all but 

 cease, the spasms give way to flaccidity of the muscles, there is insensi- 

 bility, the conjunctivas are insensitive and the pupils are widely dilated. 

 Every now and then a prolonged sighing inspiration takes place, at 

 longer and longer intervals until they cease altogether, and death en- 

 sues. During this stage the pulse is scarcely to be felt, but the heart 

 may beat for some seconds after respirations have quite ceased. The 

 condition is due to the gradual paralysis of the respiratory centre by 

 the prolonged action of the increasingly venous blood, 



As with the first stage, the duration of the second and third stages 

 depends whether the manner of the deprivation of oxygen is sudden or 

 gradual. The convulsive stage is short, lasting, it may be, only one 

 minute. The third stage may last three minutes and upward. 



The conditions of the vascular system in asphyxia are: (1) More or 

 less interference with the passage of the blood through the systemic and 

 the pulmonary blood-vessels; (2) Accumulation of blood in the right side 

 of the heart and in the systemic veins; (3) Circulation of impure (non- 

 aerated) blood in all parts of the body. 



After death from asphyxia it is found in the great majority of cases 

 that the right side of the heart, the pulmonary arteries, and the systemic 



