CIRCULATION OF CHYLE AND LYMPH. 



371 



enormous production in the presence of inflammations (pus-formation), particu- 

 larly in the case of extensive phlegmons and purulent effusions in the serous 

 cavities, when by reason of their enormous number, they cannot be regarded as 

 having resulted solely by migration from the circulation. 



The destruction of the lymph-cells appears to take place in part at 

 the seats of origin of the vessels and in the vessels themselves. The 

 occurrence in the lymph of the fibrin-factors, which are derived from 

 disintegrated leukocytes, tends to support this view. Particularly in the 

 presence of severe inflammation, especially in connective tissue, the 

 new-formation of numerous lymph-cells appears to be attended with 

 their increased destruction. Therefore the lymph under such circum- 

 stances becomes especially rich in fibrin, and, naturally, also the blood, 

 through the lymph. 



According to Hoyer, the lymph-glands are also filtering apparatus in which 

 degenerating leukocytes are intercepted and subjected to a destructive meta- 

 morphosis. 



CIRCULATION OF CHYLE AND LYMPH. 



The cause for the movement of the chyle and the lymph depends 

 ultimately on the difference in pressure prevailing between the lymphatic 

 radicles and the points at which the lymphatics empty into the venous 

 system. 



In detail the following facts are noteworthy : 



In the onward movement of the lymph, forces are primarily active 

 that are of influence at the points of origin of the lymphatics. These 

 forces must vary in accordance with the character of the points of origin, 

 (a) The lacteals receive the first motile impulse through the contraction 

 of the muscles of the villi. Inasmuch as these grow shorter and smaller, 

 they constrict the axial lymph-space, whose contents must move in a 

 centripetal direction. With the succeeding relaxation of the villus, the 

 numerous valves prevent the chyle from flowing backward. With con- 

 striction 7 of the lumen of the intestine, through contraction of the in- 

 testinal muscles, the villi are forced more closely together longitudinally, 

 the evacuation of the central lymph- vessel being likewise favored, (b) 

 Within those lymph- vessels that originate as peri vascular spaces, every 

 dilatation of the blood-vessels must cause a movement of the surrounding 

 lymph-stream in a centripetal direction, (c) Lymph enters the open 

 lymph-pores of the pleura with each inspiratory movement, which 

 excites suction upon the thoracic duct. A similar condition exists at the 

 orifices of the lymph- vessels on the abdominal aspect of the diaphragm- 

 atic peritoneum. The blood-vessels participate principally in absorption 

 from the abdominal cavity, the lymphatics relatively little. If serous 

 fluid or a solution of salt or sugar is introduced into the abdominal 

 or pericardial cavity, it will be absorbed, and, if isotonic with the blood- 

 plasma, without change; if it is not isotonic, it will first be made 

 isotonic by elimination from the blood. Accordingly, osmosis cannot 

 be alone the active agency in the process of absorption, as imbibition 

 contributes some influence. If the intra-abdominal pressure increases, 

 the blood-vessels absorb more freely, but with excessively high pressure 

 less freely, in consequence of compression of the abdominal veins. In 

 this manner is explained the clinical observation that, in the presence of 

 ascites, absorption is often promoted after the abdominal tension is 



