ON RESPIRATION 511 



the blood, the corpuscles and liquor sanguinis, are 

 respectively affected by the changes ensuing in the 

 process of aeration, and how the economy of systemic 

 in nervation is secondarily affected. Aeration of the blood 

 in the lungs is necessarily a continuous or rhythmical 

 process, which keeps pace with the pulmonary circulation, 

 as it disseminates throughout the pulmonary capillary 

 vessels, the impure blood returning from the body, 

 re-collects it after renewal or oxygenation, and returns 

 it into the heart for redistribution ; and is determined and 

 effected by a closely related cardiac-pulmonary nervature, 

 which conjoins the two sets of organs within the same 

 nervine " sphere of influence," and " operates " them by 

 the same central nervine management, so to speak, thus 

 securing a oneness of physiological purpose and a com- 

 bined functional result. 



The corpuscular, or what we may call the more 

 organised and vitalised element of the blood, undergoes 

 a visible alteration in colour in its exposure to air, 

 evidently due to chemico-physiological molecular change 

 and exchange, in its organic constituents, of a most 

 essential and far-reaching nature, in virtue of which 

 a noxiously laden metabolic vehicle becomes again the 

 bearer to " every hole and corner " of the body, of physio- 

 logically pure tissue pabulum, suitable for the anabolic 

 wants of the wasted, or katabolised, organism, which it 

 distributes with the metabolic power due to corpuscular, 

 or vital, energy and active organic chemical affinity, as 

 the varying needs of the several tissue elements demand. 



Each corpuscle of the arterial blood may thus be re- 

 garded as conveying matter and energy, derived from 

 atmospheric air and venous blood, to every organic 

 element of the body, on the expenditure of which, in 

 exchange for used-up organic elements, it once more 

 returns to the pulmonary " place of exchange," to leave 

 its used-up burden, and once more to " furnish its coffers" 

 with the required vital " currency," for the vital and 

 continuous work of organic exchange. 



Each corpuscle, moreover, being possessed of the passive 

 power of independent movement and disposal within the 

 blood stream, may be regarded as communicating with its 



