50 BIOLOGICAL PHYSICS 



Perhaps next in importance we should be entitled to place 

 the creation of molecular and atomic vacua, or voids, by 

 metabolic or katabolic displacement, due to organic work 

 and tissue exercise, and their refillment, by the selective 

 tissue attraction, with fresh molecules and atoms ; while, 

 following in dynamic importance as promoters of circula- 

 tion, we are entitled to include pure chemical affinity, or 

 attraction, and the not inconsiderable influence due to 

 capillary attractive force amid the nerve-ending intricacies 

 of fine vessels, tissue porosities, and molecular vacua. 

 These dynamic agents and others, directed and maintained 

 by vital energy, constitute the active agencies employed in 

 the organic circulatory work of every human and high 

 animal form in the maintenance of its life during its 

 " allotted span " their lapse coinciding with its death and 

 dissolution, their balanced operation constituting health, 

 their unbalanced, disease. 



We might sum up our observations on the subject of 

 circulation, as thus viewed, by saying that there is but one 

 circulation within our bodies, and that it consists of 

 alimentation in all its stages, sanguification, blood circula- 

 tion proper, nutrition, and excretion, with the almost 

 countless correlated subsidiary circulations involved in the 

 phenomena of life. 



In thus summing up we have omitted, for the sake of 

 physiological continuity, to include the aerial, or gaseous, 

 circulation, which is equally responsible, with this compound 

 fluid circulation, for the maintenance of life, but more 

 especially for the more chemical activities engaged within 

 this circulation, and in the process of metabolic change and 

 exchange of tissue elements. In the process of sanguifica- 

 tion the pulmonary aerial circulation plays a most important 

 part, passing in that most important and essential element 

 of the whole array of metabolic agencies, viz. oxygen, and 

 carrying out the redundant carbon, thus maintaining an 

 uninterrupted process of metabolic change, and an organic 

 atmosphere, so to speak, of a pure and non-toxic character, 

 amid which the manifold materio-dynamic activities consti- 

 tuting life can be carried on in untrammelled order with 

 the utmost physiological precision and success, and with a 

 vitally adjusted physical and mental balance. Circulation, 



