378 ARTHUH WILLIAM MEYER 



marrow lynii)h ghuitlsj form 1 am conviiicod, represents only a 

 transition form in dc\'eloi:)ment of hemolymph nodes from adipose 

 tissue and is to be regarded as a younger more embryonal gland." 

 Tliis opinion regarding tlie i)arallelism in early stages of develop- 

 ment between lymph and hemal nodes was expressed previously 

 by Drummond who, like Warthin, nevertheless asserted that 

 hem^,! nodes were organs sui generis. 



Warthin whose conclusions were based chiefly on observa- 

 tions made after splenectomy on sheep and goats, also stated 

 that (1) the "transformation of hemolymiph nodes into ordi- 

 nary l}anph nodes were all more marked" after splenectomy 

 and that (2) ''Tizzoni's description of their formation in [from?]' 

 adipose tissue is confirmed in every detail by the findings in 

 the above cases." According to Warthin, '02 a, "Under cer- 

 tain conditions the stages of development are of constant 

 occurrence in the prevertebral fat. Throughout the adipose tis- 

 sue of the prevertebral region there appear to be certain especially 

 differentiated fat lobules having a more definite capsule ihan 

 the surrounding lobules and a richer capillary supply, frequently 

 stand out more sharply from the surrounding fat. Under cer- 

 tain conditions [splenectomy] the capillaries of the fat lobules 

 become dilateid, the fat cells immediately about the capillaries 

 lose their fat and form a reticular network in the meshes of 

 which leucocytes assemble. Development of the capillaries 

 into blood sinuses result in a hemolytic gland, obliteration of 

 the capillaries through proliferation of the leucocytes and espe- 

 cial development of the lymphatics results in a lymph gland." 

 Elsewhere Warthin '02b, writes that "There is undoubtedly 

 a new formation of hemolymph nodes out of adipose tissue. 

 All stages of this development may be seen. The process begins 

 with an angiectatic dilation of the capillaries of a fat lobule, the 

 fat cells of which become enlarged and Ughter in color. At the 

 same time the lobule becomes fairly well set off from the sur- 

 rounding tissue by a thickening of its capsule. The next stage 

 is an infiltrat'on of lymphocytes along the walls of the distended 



^ The interrogatory is tlio writer's. 



