ABSORPTIOX 267 



the cortex that the gland is in direct communication with the 

 afferent lymphatic vessels. In the adenoid tissue of the alveolus 

 there is a network of bloodvessels ; the tissue itself is filled with 

 corpuscles known as leucocytes, which are also found in the more 

 open network extending across the lymph sinus. The medulla 

 of the gland presents no essential difference in structure to that 

 of the cortex, excepting that the reticular network is more 

 complex, closer, and more extensive. The efferent lymphatic 

 vessels originate in the lymph sinuses of the medulla. 



Lymph is a slightly yellow-coloured fluid, alkaline in reaction, 

 with a specific gravity of 1012 to 1022, and possessing the power 

 of spontaneous clotting. The clot it yields is not so firm as that 

 of blood, and takes longer to form ; moreover, the bulk of fibrin 

 is much smaller. Lymph may be regarded essentially as blood 

 minus the red corpuscles ; it contains, therefore, the proteins of 

 that fluid — viz., fibrinogen, paraglobulin, and serum albumin, 

 though in smaller amounts, also cells resembling the white cells 

 of the blood, extractives, salts, and gases. The fluid in which 

 these are contained is spoken of as lymph plasma. The gases 

 consist principally of carbon dioxide, the amount of which is 

 greater than in arterial, but less than in venous blood, a small 

 quantity of nitrogen, and only traces of oxygen. Amongst the 

 extractives some observers have found urea, a substance which 

 exists more largely in lymph than in blood, and which is said to 

 be always present in the cow. The salts are distributed much as 

 are those in blood — viz., potash in the corpuscles, and soda in 

 the plasma. It is evident that the composition of the lymph 

 cannot be uniform, but must depend, among other causes, upon 

 the nature of the food-supply and the source of the lymph. 



The lymph-cells or leucocytes exhibit amoeboid movements, 

 and are identical with white blood-cells ; they are more numerous 

 in those vessels which have passed through lymphatic glands, 

 for it is in the gland that the leucocytes are manufactured and 

 added to the lymph. The cells consist of proteins, lecithin, 

 cholesterin, and fat, and their nuclei contain nuclein. Owing to 

 their power of movement, they are able to pass through the 

 bloodvessels into the tissues, and vice versa. The proportion of 

 lymph corpuscles to fluid is about the same as the proportion of 

 white corpuscles to blood. 



The Quantity of Lymph in the Body is difficult to determine, and 

 varies considerably. From a lymphatic vessel in the neck of 

 the horse Colin obtained J to 2 kilogrammes (17 to 70 ounces) in 

 twenty-four hours ; but the variations were wide. Colin noticed 

 that the herbivora secrete more lymph than the carnivora, and 

 young animals more than adults. From the thoracic duct of a 

 cow this observer obtained the prodigious quantity of 91 kilo- 



