

CHAPTER IX. 



THE LYMPHATIC SYSTEM. 

 BY PROFESSOR F. v. RECKLINGHAUSEN. 



IN consequence of the pressure under which the blood courses 

 through the vessels of the several organs of the body, the tis- 

 sues are constantly permeated with serous fluid, which partly 

 furnishes the materials requisite for their nutrition, and is in 

 part also subservient to the preparation of the secretions. This 

 serous or tissue fluid requires constant renewal, a rapid ex- 

 change of material, without which it quickly alters the compo- 

 sition of the various tissue elements around which it plays. 

 The passage of fresh fluid from the blood into the tissues 

 would, however, cease as soon as the pressure of the latter ap- 

 proximated that under which the blood moves in the vessels, 

 were not a constant escape of the fluid provided for by means 

 of a canal system, which is so far separate from the bloodves- 

 sels supplying the tissues, that the pressure of the blood is not 

 transmitted directly into the canal system that is to say, not 

 with its full force. These canals, the lymph vessels, form 

 therefore a peculiar system, the rootlets of which are distri- 

 buted through the tissues, and which only so far stands in 

 connection with the bloodvessels, that it, 1st, indirectly with- 

 draws from them the fluid they contain, and, 2nd, that it ulti- 

 mately returns that fluid to the bloodvessels by its terminal 

 trunks. The origin of the lymphatic system is in relation with 

 the capillary vessels in which the blood moves under a con- 

 siderable pressure; its termination, on the other hand, commu- 

 nicates with the chief venous trunks, and consequently with 

 those parts of the vascular system in which the blood pres- 

 sure descends to its minimum amount, and is in fact almost 

 reduced to zero. 



