402 ORIGIN OF THE LYMPHATICS. 



absorbed by the lymphatics. A study of these conditions shows, that 

 the lymphatic system represents an appendix to the blood-vascular 

 system, and further, that there can be no lymph system when the 

 blood-stream is completely arrested ; it acts only as a part of the 

 whole, and with the whole. 



Lacteals. When we speak of the lymphatics proper as against 

 the chyle-vessels or lacteals, we do so from anatomical reasons, because 

 the important and considerable lymphatic channels coming from the 

 whole of the intestinal tract are, in a certain sense, a fairly independent 

 province of the lymphatic vascular area, and are endowed with a 

 high absorptive activity, which, from ancient times, has attracted the 

 notice of observers. The contents of the chyle-vessels or lacteals are 

 mixed with a large amount of fatty granules, giving the chyle a white 

 colour, which distinguishes them at once from the clear watery con- 

 tents of the true lymphatics. From a physiological point of view, 

 however, the lacteals must be classified with the lymphatics, for, as 

 regards their structure and function, they are true lymphatics, and 

 their contents consist of true lymph mixed with a large amount of 

 absorbed substances, chiefly fatty granules. [The contents of the 

 lacteals are white only during digestion, at other times they are clear 

 like lymph]. 



196. Origin of the Lymphatics. 



The mode of origin of the lymphatics varies within the different 

 tissues. The following modes are known : 



1. Origin in Spaces. Within the connective-tissues (connective-tissue proper, 

 bouc), are numerous stellate, irregular, or branched, spaces which communicate with 

 each other by numerous tubular processes (Fig. 157, s) ; in these communicating 

 spaces lie the cellular elements of these tissues. These spaces, however, are not 

 completely filled by the cells, but an interval exists between the body of the cell 

 and the wall of the space, which is greater or less according to the condition of 

 movement of the protoplasmic cell. These spaces are the so-called "juice-canals " 

 or " saftcanalchen," and they represent the origin of the lymphatic vessels (v. 

 Reckliughausen). As they communicate with neighbouring spaces, the movement 

 of the lymph is provided for. The cells which lie in the spaces, and which were 

 formerly but erroneously regarded by Virchow as the origins of the lymphatics, 

 exhibit amoeboid movements. Some of these cells remain permanently, each in its 

 own space, within which, however, it may change its form these are the so-called 

 "fixed " connective-tissue corpuscles, and bone-corpuscles while others merely 

 wander or pass into these spaces, andare called "wandering cells," or "leucocytes;" 

 but the latter are merely lymph-corpuscles, or colourless blood-corpuscles which 

 have passed out of the blood-vessels into the origin of the lymphatics. These cells 

 exhibit amoeboid movements. These spaces communicate with the small tubular 

 lymphatics the so-called lymph-capillaries (L). The spaces lie close together 

 where they pass into a lymph-capillary (a). The lymph-capillary, which is 

 usually of greater diameter than the blood capillary, generally lies in the middle 



