242 ARTHUR WILLIAM MEYER 



In spite of the confessed impossibility of distinguishing between 

 lymph and hemolymph nodes Lewis and Warthin formulated 

 rather elaborate classifications in which the lymphatico-hemal 

 structures of 'the body were divided into lymphatic, hemal-lym- 

 phatic, and hemal nodes. According to Lewis, two types of 

 hemal nodes with an intermediate form, and three types of hemal 

 lymphatic glands can be distinguished. Warthin (46) suggested 

 a further division in spleno- and marrow hemolymph nodes and 

 Morandi and Sisto (25) divide human hemolymph nodes into 

 six groups even. Weidenreich (51) also distinguished several 

 types of hemolymph nodes but upon the basis of injections never- 

 theless concluded that hemolymph nodes as a class have no 

 connection with the lymphatic system. The latter was, how- 

 ever, denied by Helly (19) and Forgeot (11) who claimed that 

 hemoljrmph glands did not only contain lymphatics but that all 

 manner of transition forms could be found in which lymphatic 

 vessels simply were near the hilus, in the hilus, and in various 

 stages of penetration of the node. A similar position is also 

 taken by v. Schumacher (4) who concluded that a lymph node 

 may become a hemolyraph node and finally perhaps again a 

 lymph node by the disappearance and perhaps the re-entrance 

 of lymphatics, v. Schumacher also considered the hemal node 

 as a rudimentary form of ordinary lymph nodes and divided the 

 latter into those with and without lymphatics. 



As will be reported elsewhere, a very large series of injections 

 directly on the carcasses of sheep, has led to the positive conclu- 

 sion that Weidenreich was correct when he decided as a result 

 of similar injections that the true, not the so-called, hemolymph 

 nodes have no connection with the lymphatic system. If this 

 is true it follows, of course, that this is a simple and crucial test 

 for differentiating lymph and hemol3miph nodes although v. 

 Schumacher denies the latter. By means of it the alleged pro- 

 duction of hemolymph nodes under various conditions can also 

 be tested easily. If, for example, certain apparently newly-formed 

 nodes are found or if lymph nodes have apparently been trans- 

 formed into hemolymph nodes, the identity of the former and 

 the absence of lymphatic connections in the latter can readily 



