206 MANUAL OF PHYSIOLOGY. 



4. Increase of the amount or the pressure of the blood flow- 



ing- through any part augments the lymph flow. 



5. The administration of curare increases the amount of lymph. 



The history of the structural elements or lymph corpuscles, 

 which exist in such numbers in the large lymph channels, re- 

 quires some further discussion, as these cells are composed of 

 active protoplasm and therefore must be destined for some im- 

 portant function, and are produced-by some vital process. 



The origin of the lymph corpuscle- is not restricted to any one 

 part of the body or to any special organ. It has been said already 

 that the lymphatic glands are supposed to be the most important 

 source of these cells, because the follicular tissue is filled with 

 them, and the lymph contains a much larger number after it has 

 passed through some lymph glands. In the lymphoid tissue of 

 the spleen they are also very numerous, and no doubt many of 

 them have their origin in that organ as well as in the intestinal 

 follicular tissue and in the red marrow of the bones. Although 

 their number is relatively small, lymphatic cells occur in the 

 lymph channels that are unconnected with a lymphatic gland, 

 and these cells no doubt come from the blood, which, as we shall 

 see, contains many cell elements, which are actually the lymph cells 

 poured into it from the lymphatic duct. These cells, when they 

 arrive at the minute bloodvessels, sometimes leave the vessels and 

 creep by amo3boid movements into the interstices of the tissue, along 

 with the irrigation stream. They may permanently abide in the tis- 

 sue, or they may be washed back into the larger lymph channels 

 with the stream of surplus lymph. When the abnormal increase 

 of activity of a tissue known as inflammation, occurs, this escape of 

 the white cells from the blood takes place with great rapidity, and 

 the stages in the process can be watched under the microscope. 



Still another source of the lymph cells may be from prolifera- 

 tion of the cells which lie in the tissues. The fixed tissue-cells 

 are said to be capable of producing cells identical with lymph 

 cells, and, by division, possibly multiply and produce their like, 

 which may be carried along by the lymph stream as lymph cells. 



The enormous number of cells which accumulate as pus when 

 an abscess, forms, are structurally identical with lymph cells, and 



