382 ARTHUR WILLIAM MEYER 



siinie \vlii(;li arc usiuilly distributed about freely in the paren- 

 chyma of the heinal node are removed. 



The difficulty of such an assumed transformation becomes 

 tloubly evident if the occurrence^ of ve-ry large numbers of hemal 

 nodes which represent practically nothing but a sack of blood, 

 is borne in mind. Moreover, if such a transformation did occur, 

 it would seem exceedingly strange that some carcass among 

 the many thousands examined did not have a number or a 

 group of lymph nodes in the fat of the sub-vertebral or subcu- 

 taneous regions, or elsewhere, at least approximately equiva- 

 lent to the number of hemal nodes commonly found there. It 

 would also seem strange that some hemal node or nodes with 

 afferent lymphatics in various stages of entrance or penetration 

 into the nodes were not found among the many, many hundreds 

 of nodes examined macroscopically and microscopically. Fur- 

 thermore, if lymph nodes can be transformed into hemal nodes 

 some carcasses in which the customary lymph nodes in the 

 lumbar sub vertebral region had" all been transformed into hemal 

 nodes should have been found or there should, at least, have 

 been a decided reduction in the number of lymph nodes in car- 

 casses in which hemal nodes were so very numerous in this or 

 in another region. Such reciprocal relations were, however, 

 never observed and it is to be very seriously questioned whether 

 they occur at all. Indeed, the evidences presented establish- 

 ing such a transformation have been wholly inadequate, and 

 no evidences whatever for such an assumption were observed 

 in the course of my series of investigations which included large 

 numbers of individuals in nine different species. 



Great difficulties confront those who conclude that hemal 

 nodes are only modified lymph nodes which may again be recon- 

 verted and thus cease to exist as hemal nodes. From a com- 

 parative anatomical standpoint it would seem strange indeed 

 that this accident (?) in development is restricted not only to 

 certain species and that it should predominate in certain re- 

 gions of a given species, but that it occurs so much more fre- 

 quently in some individuals — or at some ages — of a given species 

 than in the case of others. Moreover, since the sub-pannicular 



