ON THE BLOOD 507 



in the body. So long, therefore, as the physiological 

 balance between the two elements characterises the com- 

 position of the blood and its distribution, so long will 

 the health of the body be maintained ; but so soon as 

 that balance is disturbed, in like manner will it be 

 followed by a proportionate pathological departure from 

 that condition. 



Besides the functions above, merely hinted at or 

 implied, we must be prepared to find that there exists 

 in the blood machinery, apart from, but intrinsically resident 

 in it, a most elaborate system of chemical attraction and 

 repulsion, and a power of physiological assortment by which 

 the fresh or nutritive plasmic elements are separated, or 

 rather kept separate, from the used-up or non-nutritive, 

 and the processes of metabolism and integration of tissue 

 secured and maintained, while simultaneously the hygiene 

 of the whole vital area is accomplished by appropriate 

 systemic effluents, or excretionary agencies, the main 

 examples of which may be adduced as the intestinal, the 

 renal, the pulmonary, and the cutaneous. 



The performance of such many-sided chemico-physio- 

 logical work, as thus outlined, not only implies, but 

 necessitates, the existence, within the apparently simple 

 and elemental blood fluid, of a most elaborate organic 

 and organising machinery, as we have said ; and this we 

 are warranted in seeing in, and assigning to, its corpus- 

 cular elements, from their ubiquitous existence, their high 

 structural character, their power of lending themselves to 

 circulatory disposal, and their absolutely living condition, 

 with their dynamically active ability to dispose or dis- 

 tribute, and chemico- physiologically assort, the blood 

 plasma into the elemental constituents of the various 

 structural elements of the body, while at the same time 

 engaging in the vital work of removal of effete and used- 

 up or katabolic materials. 



Thus a vital chemistry is at work here which must 

 baffle the most skilful experimentation to imitate, and 

 which oversteps the tiny environments of science as yet 

 known and practically applied, and reduces to one com- 

 posite whole the ever active vital physics and dynamics 

 of organism to the end that life may be begun, continued, 



