37# PHILOSOPHICAL TRANSACTIONS. [anNO 1698. 



On the Cause and Use of Respiration. By Dr. Musgrave, F.R. S. dated Exeter, 



May y, 1698. N° 240, p, 1/8. 



Nothing is more evidcMit than that breathing is, from the very moment of 

 our birth, perpetually necessary to life ; yet nothing is more in the dark than 

 the true cause and reason of that necessity. Dr. Thruston asserts that the chief 

 use of respiration consists in maintaining a due motion of the blood. And to 

 make out his assertion he urges, that this opinion easily explains the manner of 

 sudden death, by strangling, by drowning, and by violent catarrhs, supposing 

 death, and the stagnation of the blood in the lungs, right ventricle of the heart, 

 &c. to arise, in all these cases, from the stoppage of the breath. Etmuller 

 embraces the same opinion. 



Though I think the opinion is very rational, I cannot say it appears such 

 from the argument now produced, which, on examination, will be found too 

 liable and obnoxious to bear so great a proportion of the proof. By Dr. 

 Thruston's own concession, men that are hanged may, with good reason, be 

 supposed to die partly from the mutual commerce between the head and heart 

 being intercepted. The remarkable lividness of their faces, with the extraor- 

 dinary distension of the jugulars, in their several branches above the ligature, 

 argue that they die in a great measure apoplectical. Now, whatever share the 

 interruption of this mutual commerce has in killing the man ; so much the less 

 reason have we to impute his death, and the stagnation of blood in his lungs, 

 &c. to the stoppage of his breath. Nor is the second case, that of sudden 

 death by drowning, without exception : for here -the water rushing, after an 

 unusual manner, into the lungs,* may be suspected so to affect them as to oc- 

 casion death, though not by stopping the circulation. And as to suffocation 

 from a catarrh, instances of this kind, with anatomical observations on them, 

 have not occurred sufficient to prove what was intended by this argument. 

 Wherefore that a noble proposition may not want evidence, I pitched on the 

 following experiment, as clear and decisive of the matter. 



I took a large middle aged healthy dog, and having freed the trachea from 

 the adjacent parts, cut it off just beneath the pomum adami, and turned the 

 loose end outward. After some time allowed him to recover the present con- 

 cern, with a cork got ready on purpose, I stopped up the trachea, binding it 



* Very little water is found in the lungs of drowned animals. Their death is not occasioned (as 

 Dr. Musgrave supposed) by tiie rushing of the fluid in which tiiey are submerged into the tnuhea 

 and bronchia, (see Goodwyn on the Connexion of Life with Respiration,) but to the distoutinuance 

 of die oxygenizement and other chemical changes of the blood, in consequence of the necessary 

 supply of atmospherical air being cut otf. 



