THE LYMPH AND CHYLE. 37 



inconsistent with this theory to admit the positive efficacy of contact with foreign 

 or dead matter in promoting- coagailation. Lister,* on the other hand, considers 

 that the blood has no spontaneous tendency to coagulate, either within or without 

 the vessels, but that the coagulation is brought about in di-awn blood by contact 

 with foreign matter. Accepting the conclusion of Schmidt, that para-globulin 

 and fibrinogen are necessary to the evolution of fibrin, he thinks that, if these 

 bodies unite in ordinary chemical combination, the action of foreign matter may 

 detennine their imion, as spongy platinum promotes the combination of oxygen 

 and hydrogen. He considers that the li\dng vessels do not exert any action to 

 prevent coagulation, but that their peculiarity, as distinguished from an ordinary 

 solid, consists in the remarkable circumstance that their lining membrane, in a 

 state of health, is wholly negative in its relation to coagulation, and does not 

 cause that molecular disturbance, so to speak, which is produced in the blood by 

 all ordinary matter. \Mien the vessels lose their peculiar property' by death, or 

 become seriously altered by disease or injury, their contact with the blood in- 

 duces coagulation like that of an extraneous body. More recently, Schmidtf has 

 himself come to the conclusion that the union of para-globulin and fibrinogen to 

 form fibrin is determined by the presence of a third substance, which, however, 

 does not itself take part in the combination and which he has consequently 

 named the fibrin-ferment. Tliis substance he believes to be not preformed in the 

 blood, but to become formed immediately after the withdrawal of that fluid from 

 the body. Other substances also, according to Schmidt, possess the property of in- 

 ducing the union of para-globulin and fibrinogen, amongst them being the coloimng 

 matter of the blood.J charcoal, spongy platinum, asbestos, animal fennents, &c. ; 

 more especially those which are able to decompose peroxide of hydrogen. Schmidt 

 considers the action of these substances to be purely one of contact ; in this 

 respect it will be seen he has adopted Lister's view. Finally, it may be observed, 

 that in any attempted explanation of the coagulation of the blood, it is well to 

 bear in mind that there is a purely physical or chemical phenomenon, which, as 

 suggested by Graham, has a certain analogy to it. namely the change from the 

 liquid to the insoluble state so easily induced in colloidal matter by slight external 

 causes, 



THE LYMPH AND CHYLE, 



A transparent and nearly colourless fluid, named " lymph," is con- 

 veyed into the blood by a set of vessels distinct from those of the 

 sanguiferous system. These vessels, which are named " lymphatics," 

 from the nature of their contents, and " absorbents," on account of 

 their reputed office, take their rise in nearly all parts of the body, and, 

 after a longer or shorter course, discharge themselves into the great 

 veins of the neck ; the greater number of them previously joining into 

 a main trunk, named the thoracic duct, — a long narrow vessel which 

 rises up in fi'ont of the vertebra?, and opens into the veins on the left 

 side of the neck, at the angle of union of the subclavian and internal 

 jugular ; whilst the remaining lymphatics terminate in the correspond- 

 ing veins of the right side. The absorbents of the small intestine 

 carry an opaque white liquid, named " chyle," which they absorb from 

 the food as it passes along the alimentary canal ; and, on account of 

 the milky aspect of their contents, they have been called the " lacteal 

 vessels." But in thus distinguishing these vessels by name, it must be 

 remembered, that they differ from the rest of the absorbents only in the 

 nature of the matters which they convey ; and that this difference holds 



* On the Coagulation of the Blood ; the Croonian Lecture for 1S63. — Proceedings of the 

 Eoyal Society, vol. xii. p. 580. 



+ Pfliiger's Arcbiv. vi. 1872. 



+ In connection with this fact, it may be interesting to mention that, if blood which 

 has been well whipped to remove the fibrin be frozen and thawed again (a process by 

 whicli the red corpuscles become broken up), it yields a further coagulum. 



