108 HUMAN PHYSIOLOGY. 



It is then passed onward into the interior of the villus to enter the blood 

 stream. 



The soap and glycerin after absorption are synthesized to fat which is 

 deposited in the epithelial cells in the form of small drops, after which it 

 too passes to the interior of the villus to enter the lymph capillary. 



The products of digestion find their way into the general circulation by 

 two routes: 



1. The -water, protein, dextrose, and soluble salts, after passing into the lymph- 

 spaces of the villi, pass through the wall of the capillary blood-vessel; 

 entering the blood, they are carried to the liver by the vessels uniting to 

 form the portal vein; emerging from the liver, they are emptied into the 

 inferior vena cava by the hepatic vein. 



2. The fat enters the lymph-capillary in the interior of the villus; by the 

 contraction of the layer of muscle-fibers surrounding it its contents are 

 forced onward into the lymph-vessels or lacteals, thence into the thoracic 

 duct, and finally into the blood stream at the junction of the internal 

 jugular and subclavian veins on the left side. 



Properties and Composition of Lymph. Lymph, as found in the 

 lymph-vessels of animals, is a clear, colorless, or opalescent fluid, having 

 an alkaline reaction, a saline taste, and a specific gravity of about 

 1040. It holds in suspension a number of corpuscles resembling in their 



COMPOSITION OF LYMPH. 



Water 95 .536 



Proteins (serum-albumin, fibrin-globulin) 1-320 



Extractives (urea, sugar, cholesterin) i . 559 



Fatty matters a trace 



Salts 0.585 



100.000 



general appearance the white corpuscles of the blood. Their number has 

 been estimated at 8,200 per cubic millimeter, though the number varies in 

 different portions of the lymphatic system. As the lymph flows through 

 the lymphatic gland it receives a large addition of corpuscles. Lymph- 

 corpuscles are granular in structure, and measure ^sVo f an mc h m 

 diameter. When withdrawn from the vessels, lymph undergoes a spon- 

 taneous coagulation similar to that of blood, after which it separates in 

 serum and clot. 



Origin and Functions of Lymph. Though the blood is the common 

 reservoir of all nutritive materials, they are not available for nutritive purposes 



