90 ELEMENTARY PHYSIOLOGY. 



have learned also that the blood-vessels both give 

 off tissue-making substances and take on waste and 

 worn-out material, which they carry away. In con- 

 trast with this the lymph does not "circulate." It is 

 carried toward the heart, where it enters the life- 

 giving stream the blood. In the lymphatic system 

 there are, therefore, no vessels to correspond with 

 arteries. Again, the lymphatics collect worn-out tis- 

 sues, etc., but give nothing in return. 



The work of the lymphatics is not Con- 

 Other Func- J . r 



tions or the fined to the absorption of food from the 

 Lymphatics. i n t es ti neg an( j collecting surplus and 



waste materials from the system in general. Certain 

 other phenomena, all of which are of interest to us, 

 are due to the absorbing power of these vessels. For 

 instance, when a poisonous substance is placed upon 

 the skin the lymphatics at once absorb it and carry 

 it into the circulation. The lymphatics of the lungs 

 take in the poison of disease and diffuse it through- 

 out the system. When the appetite fails during 

 long-continued illness, life is sustained by the uncon- 

 scious consumption of one's own flesh, which is 

 absorbed by the lymphatics and carried out into the 

 circulation. 



In a similar manner, as we will learn further on, 

 the poisonous nicotine of tobacco is absorbed in the 

 lungs and the system poisoned. Thus we see that 

 these vessels, which are ever active, take up, indis- 

 criminately, foods, poisons, medicines, or the waste 

 of worn-out material 



