Floronee i\. .Sabin 



383 



portions of the lyniphoid tissue and the lymphatic tissue. Sometimes 

 the lymphoid tissue, that is, tlie connective tissue ])ortion with lympho- 

 cytes arouiul the artery, nearly fills the node while in other cases the 

 lymphatic ducts predominate. 



Development of the folJlde liKtepenileiitli/ of the h/iitplt duels. — 

 One im})ortant fuiuhimental jioint comes out in the study of these 



K.10<v. 



Fig. 16. Group of microscopic lymph follicles in the neighborhood of the 

 inguinal lymph node in an embryo pig, 24.5 cm. long, x about 72. The 

 condition of the main inguinal node at this stage, is shown in Fig. 14. A. 

 follicles consisting of lymphocytes around a tuft of blood capillaries; &. 

 follicles with a single peripheral sinus; c, follicles which are made mainly of 

 a plexus of lymph ducts; Id, large lymph duct; Ip, lymph plexus in the border 

 of a large lymph node. 



various mxlc^. After a certain sta.iic in development, the larg-e nodes, 

 especially those that develop in the Ion-;- ple.xus and in the inguinal 

 region, show many microscopic nodes in their neighborhood. These 

 microscopic nodes are abundant in emliryos from 2"? cm. long on. Fig. 16 

 is a section in the ])order of the inguinal node in a pig 24..") cm. long, 



