xlviii THE LYMPH AND CHYLE. 



may now consider the lymph and the chyle, which, as will be seen, are 

 intimately related to the blood. 



LYMPH. 



The lymph may be procured free from admixture of chyle, and in quan- 

 tity sufficient for examination, from the larger lymphatic vessels of the 

 horse or ass. It may also be obtained by opening the thoracic duct of an 

 animal that has fasted for some time before being killed. It is a thin 

 fluid, transparent and colourless, or occasionally of a pale yellow hue ; 

 its taste is saline, its smell faint and scarcely perceptible, and its reaction 

 alkaline. Sometimes the lymph has a decided red tint, of greater or less 

 depth, which becomes brighter on exposure to the air. This redness is due 

 to the presence of coloured corpuscles, like those of the blood : and it has 

 been sometimes supposed, that such corpuscles exist naturally in the lymph, 

 in greater or less quantity ; but they are more probably introduced into the 

 lymphatic vessels accidentally. It can, in fact, be shown that when an 

 incision is made into a part, the blood very readily enters the lymphatics 

 which are laid open, and passes along into larger trunks ; and in this way 

 blood is conveyed into the thoracic duct, or any other large vessel, exposed 

 as usual by incision immediately after the animal is killed. Indeed, mere 

 rough handling of some organs, such as the liver and spleen, will rupture 

 the fine vessels and cause the contents of the issuing lymphatics speedily to 

 become red from admixture of blood. 



The lymph, when examined with the microscope, is seen to consist of a 

 clear liquid, with corpuscles floating in it. These "lymph-corpuscles," or 

 lymph- globules, agree entirely in their characters with the pale corpuscles 

 of the blood, which have been already described (page xxxi. ). It is alleged 

 that some of the lymph corpuscles have a yellowish tint. Occasionally, 

 smaller particles are found in the lymph ; also, but more rarely, a few oil 

 globules of various sizes, as well as red blood-corpuscles, the presence of 

 which has just been referred to. 



The liquid part (lymph -plasma) bears a strong resemblance in its physical 

 and chemical constitution to the plasma of the blood ; and accordingly, 

 lymph fresh-drawn from the vessels coagulates after a few minutes' expo- 

 sure, and separates after a time into clot and serum. This change is owing 

 to the combination of the constituents of the fibrin contained in the lymph- 

 plasma, and in this process most of the corpuscles are entangled in the 

 coagulum. The serum, like the corresponding part of the blood, consists 

 of water, albumen, extractive matters, fatty matters in very sparing quan- 

 tity, and salts. Sugar exists in small quantity in the lymph, and urea, in 

 the proportion of from O'Ol to 0'02 per cent. ; leucin has also been found, 

 at least in the lymphatic glands. 



Human lymph has been obtained fresh from the living body in several 

 instances, from lymphatic vessels, opened by wounds or other causes. It 

 has been found to agree in all material points with the lymph of quad- 

 rupeds. 



CHYLE. 



The chyle of man and mammiferous animals is an opaque, white fluid, 

 like milk, with a faint odour and saltish taste, slightly alkaline or alto- 

 gether neutral in its reaction. It has often a decided red tint, especially 

 when taken from the thoracic duct. This colour, which is heightened by 



