DIGESTION AND ABSORPTION. 



113 



tain is called, does not " circulate." The blood starts from 

 the heart, and is brought around 

 back to the heart again. The 

 lymph starts from all parts of the 

 body, and is brought in toward 

 the heart. If you compare the 

 lymphatic vessels with the capil- 

 laries and veins, you have nothing 

 in this system to correspond with 

 the arteries. 



The capillaries of the lymphatic 

 system form networks which are 

 interwoven with the networks 

 made by the capillaries of the cir- 

 culatory system. Where the blood 

 capillaries are numerous, the lym- 

 phatic capillaries are numerous. 

 Where the blood capillaries are 

 wanting, the lymphatic capillaries 

 are wanting. In the skin, the net- 

 work of capillary blood-vessels is 

 spread out nearest the surface. 

 The network of lymphatics lies be- 

 neath. The two sets of vessels are 

 always found near together. This 

 would lead us to suppose that they 

 worked together. When we study 

 their action, we find that they do. 

 But the blood-vessels both give to 

 the tissues from their contents, and 

 take from the tissues their waste. 

 The lymphatics give nothing to the tissues: they only 

 take from them. 



Fig. 45. 



LYMPHATICS. 1. Lymphatic 

 ducts. 2. Lymphatic glands. 



