INTRODUCTION 9 



order that an answer may more readily and completely be 

 obtainable to the former. 



What circulatory experiences does that portion of the 

 blood which reaches the lymphatic vasculature pass through 

 in becoming the specific fluid called lymph? is the question 

 to be dealt with. We do not concern ourselves with the 

 present views held on the subject more than that we shall 

 endeavour to take advantage of all their teaching in order 

 to keep ourselves in harmony with the trend and spirit of 

 research. The alimentary circulation having ended in the 

 blood circulation, and the blood circulation having con- 

 veyed to its capillary vasculature the nutrition-laden blood, 

 what next takes place ? 



The red blood corpuscles after undergoing changes, 

 especially of a chemico-physical order, pursue their course 

 back to the heart for pulmonary aeration and renewal, 

 while the white pursue a still somewhat debatable course, 

 some, it may be, accompanying the red on their return to 

 the heart, and some escaping through the inter-spaces of 

 the lining endothelial cells, as "wandering cells" appearing 

 amid the tissue elements as leucocytes, phagocytes, and 

 others of "that ilk." 



Meantime the proper nutritive elements floated in the 

 liquor sanguinis are taken up by the endothelial cell 

 osmosis, and passed as plasma into the bodies and nuclei 

 of the cells composing the capillary lining, whence they 

 are conveyed by the endothelial cell processes to neigh- 

 bouring deeper cells, and layers of cells, and tissue elements 

 proper, these cell processes being patent to the flow and 

 permeable to the conveyance of physiologically prepared 

 fluids, once more evidencing the principle of circulation 

 as the all-pervading method of organic conveyance. 



It is impossible to conceive the conveyance from the 

 blood to the tissues of the elements of nutrition, or meta- 

 bolism, on any other lines than those of continuity of 

 lumina of circulatory ways, and thus we are warranted in 

 inferring that the lining capillary cells take up through 

 their walls into their bodies the nutritive plasma designed 

 to meet the metabolic requirements of their individual 

 organisms, and pass on what remains unused by their 

 processes, and what is required for the nourishment of 



