464 PHYSIOLOGY OF THE DOMESTIC ANIMALS. 



When freshly drawn from the thoracic duct of fasting animals, 

 lymph is a transparent, slightly yellowish fluid ; when collected during 

 digestion, it is milky from the fat in suspension derived from the chyle. 

 When examined under the microscope, lymph is seen to contain color- 

 less corpuscles, identical with the colorless blood-corpuscles, floating in 

 a clear lymph-plasma: these corpuscles are much fewer in number in 

 lymph drawn from the lymphatic radicals, while they are comparatively 

 abundant in the tymph as it issues from the lymphatic glands. Although 

 the lymphatic glands are the principal manufacturers of the lymph-cor- 

 puscles, they are not their sole source. The lymph-cells also originate 

 wherever adenoid tissue is found, as in the mucous membrane of the 

 stomach and intestines, in the thymus, tonsils, and spleen. 



The lymph of animals in active digestion is milky from admixture 

 with the fatty clryle : such lymph is said to have a molecular basis from 

 .the finely divided fat-globules which it holds in suspension. These par- 

 ticles often exhibit Brownian movements. 



The amount of lymph can only be approximately estimated. It has 

 been reckoned that for every two hundred and twenty pounds of body 

 weight there is contained in the body about thirteen and a half pounds 

 of lymph and chyle seven and a half pounds being chyle and six 

 pounds lymph. As much as six kilos of tymph have been collected in 

 two hours from the lymphatic trunk in the neck of the horse, w r hile in 

 twenty-four hours ninet3'-five kilos of lymph and chyle have been col- 

 lected from the thoracic duct of the ox. The amount of these two fluids 

 (lymph and chyle) will evidently increase during digestion. Active and 

 passive movements and increased blood pressure, as well as obstruction 

 of the veins, by facilitating transudation from the blood-vessels, will 

 increase the amount of lymph. 



Lymph is a viscid fluid, slightly less alkaline than blood, having 

 a specific gravit}' that varies from 1022 to 1037, or occasionally as high 

 as 1045. When removed from the body it coagulates in from five to 

 twenty minutes, the process being analogous to the coagulation of blood- 

 plasma, though much slower, perhaps on account of its high alkalinity. 

 The coagulation of lymph may be accelerated by the addition to it of a 

 few drops of defibrinated blood b}^ the addition thus accomplished of 

 fibrin factors in larger amount. A soft, trembling jelly is first formed, 

 which gradually contracts, expressing out a clear lymph-serum, in which 

 floats a colorless contracted coagulum, composed of fibrin which is iden- 

 tical with that formed in blood coagulation. 



From 1000 parts of the lymph of a foal, Schmidt determined that 

 955.17 were serum, while only 44.83 were coagulum. After death the 

 lymph usually remains perfectly fluid in the lymphatics, and does not 

 coagulate when the lymph-current is arrested during life. 



