348 STRUCTURE OF THE SHEEP. 



than that of the chest in respiration, yet there is a most in- 

 timate connexion between the one and the other ; for, be- 

 sides the changes which we have spoken of in the blood, it 

 rushes into the heart when the chest is expanded, and when, 

 from any cause, respiration is delayed, the pulse becomes 

 less frequent and more languid in consequence of the ob- 

 struction in the current of the blood. Thus, in violent fits 

 of coughing, the chest collapses, the air is expelled, and the 

 blood not being purified, is unfit for circulation, and the con- 

 sequence is the veins of the head become distended, and, 

 in man, the person becomes red or black in the face, and 

 sometimes a blood-vessel has ruptured and death super- 

 vened. 



