1904.] Breathing, in Living Beings. 475 



WEEKLY EVEXING MEETING, 



Friday, March 4, 1904. 



Sir James Criohton-Browne, M.D. LL.D. F.R.S., Treasurer 

 and Vice-President, in the Chair. 



William Stirling, M.D. D.Sc. LL.D., Professor of Physiology, and 

 Dean of the Medical Faculty of the University of Manchester. 



Breathing, in Living Beings. 



(abstuact.) 



May I crave your lenient judgment during a passing hour ? The 

 subject is so vast, and the time so short, that I hardly feel equal to 

 the task. 



I hope you will season your just criticisms with a sprinkling of 

 the sweet waters of mercy. If so, I am encouraged to proceed at 

 once to give a short account of some of the mechanisms related to the 

 process of breathing in living beings. 



It has been said that the most striking facts connected with 

 respiration are its universality and its continuity. In popular language 

 " the breath is the life." Breathing is not only a sign of life, it is a 

 condition of its existence. Permanent cessation of breathing is re- 

 garded as a sign of death. Link up with this the icy coldness of death 

 and you have two significant facts. 



Eespiration and calorification are therefore intimately related ; in 

 fact, calorification is one form of expression of the results of respira- 

 tory activity. 



The popular view of respiration is an inference from what is 

 observed in man and animals. During life the rise and fall of the 

 chest goes on rhythmically from the beginning to the end. The 

 respiratory exchanges effected in the breathing organs — lungs or 

 gills — constitute " external respiration." This, however, scarcely 

 touches the main problem, viz. what is called " internal respiration," 

 or tissue respiration — i.e. the actual breathing by the living cells and 

 tissues which make up a complex organism. 



We are told that man does not live by bread alone. We know 

 he requires, in addition, solids, fluids, and air. Taking these to 

 represent the three graces, then air is of all the graces best. 



The higher animals have practically no reserve stores of air — 

 unlike what happens with the storage of fats and proteids — and hence 

 the necessity for mechanisms by which air is continually supplied to 

 the living tissues, and also by which the waste product of combustion, 



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