CHAP. XXVI.] LYMPH AND CHYLE. 283 



thoracic duct of a small dog, in the course of a few minutes, as much 

 as will fill a watch-glass. If absorption is actively going on at the 

 moment, a ligature on the duct will often be followed by a rapture 

 of some vessel below by the onward pressure of the current. So the 

 lymph, in some instances, has been collected in considerable quan- 

 tity in a short space of time. Geiger, from an open lymphatic on the 

 foot of a horse, collected from three to five pounds of lymph daily. 

 Bidder has performed some experiments on cats, from which he 

 estimates that a quantity of lymph and chyle, together equal to one- 

 sixth the weight of the body, or the whole weight of the blood, enters 

 the circulation every twenty-four hours. But it must be borne in 

 mind, that this does not all form new supply, the lymph being, 

 probably, in large measure derived from that liquor sanguinis which 

 has escaped from the capillaries into the interstices of the tissues, 

 and which cannot re-enter the capillaries in a direct manner. 



Mechanism of Absorption. In considering this part of the sub- 

 ject, the following points should be remembered : 



1. The process of absorption in living bodies, implies imbibition by their 

 tissues, and subsequent transmission of the imbibed fluid, by the vascular 

 channels, to distant parts. 



2. As regards imbibition, it is a phenomenon of a purely physico-chemical 

 nature, and occurs in inorganic as well as organic bodies, and in organic bodies 

 both when dead and living. It depends mainly on the force of adhesion, 

 between a fluid and a porous solid, by which the fluid is drawn into the in- 

 terstitial passages of the solid. 



3. The fluid chiefly concerned in this process, in all animal and vegetable 

 bodies, is water ; which, as already stated, has a close affinity for their tissues, 

 and forms an essential ingredient of them, without which they, for the most 

 part, lose their vital and physical properties. 



4. The various other substances which are imbibed in living bodies, are taken 

 up in a state of aqueous solution, such as gases, albumen, fibrine, salts, etc. 



5. Where the fluid is rendered complex by holding in solution various sub- 

 stances which have different degrees of the force of heterogeneous adhesion 

 for each other, for the water they are dissolved in, and for the porous solid, 

 the phenomena of their transmission are also complex ; various preferences, 

 if we may so express it, exist ; one ingredient penetrates rather than another, 

 and the results depend very much on the chemical qualities of the elements 

 concerned. 



6. The laws relating to the mixture of different fluids also exert an impor- 

 tant influence on the phenomenon. 



Referring to a former page (vol. i. p. 53) for a brief notice of the 

 phenomena of endosmose and exosmose, as observed by Dutrochet, 

 we may conveniently proceed with the consideration of the mechan- 

 ism of absorption in the living body, under the following heads. 



Absorption as influenced by the Qualities of the Fluids. It was 



u 2 



