512 BIOLOGICAL PHYSICS 



neighbouring corpuscles, and thus by itself, or through 

 them directly, or indirectly, with every cell lining the 

 blood vasculature, and thence with every cell directly 

 associated by contiguity of cell body, or continuity of 

 cell process, with that vasculature, hence the influence 

 of the corpuscle may be said to be felt universally through- 

 out the haemal, and associated structural, or organic, 

 elements of the body. 



The liquor sanguinis, the other great blood element, 

 may be regarded as conveying everywhere, in somewhat 

 like manner, the perhaps less organised and vitalised 

 constituents of tissue plasma supplying the structures 

 requiring such, and re-collecting by osmosis, perhaps, 

 certain lymphoid elements of tissue waste, for conversion 

 to future use, or for elimination through the various 

 excretory agencies of the body and the lungs, the bowel, 

 or intestinal canal, the kidneys, and the skin. 



That the alimentary elements, organic and inorganic, 

 solid, liquid, and gaseous, entering the body, and requir- 

 ing for their metabolic disposal the services of its entire 

 organic machinery, are, under normal physiological condi- 

 tions, exactly balanced in weight and chemical equivalents 

 by waste products in the form of the materials transpired, 

 exhaled, exuded, and excreted, or leaving the body, is 

 a statement, the truth of which, on such grounds as the 

 above, must now be accepted as axiomatic. When the 

 physiological estimate of the quantity of ingesta necessary 

 for the maintenance of physiological health has been 

 formed, it behoves that that estimate ought always to 

 be the basis of demand and supply, and that any departure 

 from it ought to be made on true physiological lines. 

 The quality, as well as quantity of the ingesta, however, 

 must also be subject to physiological determination and 

 limitation as well, or a departure from the standard of 

 physiological health must ensue, of a magnitude propor- 

 tionate to the departure from the physiological rule of 

 choice. In this latter respect the lower animals, and some 

 of our more savage fellow-creatures, maintain a higher 

 standard of choice, in respect of quantity and quality, 

 when free to choose, than does so-called civilised man ; 

 and so maintain the continuity of physiological health 



