368 



Develo])nu'nt of the Lviiiplialie Xodcs in the Pig 



in a series of five diagrams. Each diagrain is made from a single section 

 traced with the aid of the camera lucida. The blood-vessels are put in 

 freehand from the study of the complete set of serial sections from which 

 each diagram was made. All the figures are of the same magnification. 





Fig. 9. Primary lymph node from a transverse section of the neclv of an 

 .embryo pig 4.9 cm. long, x about 44. The section is placed similar to Fig. 8. 

 Ld, afferent lymph duct; Ih. lymph heart; v, vein. 



about 33 diameters. The lymphatic vessels are shown in solid black as 

 if injected, while the connective tissue of the hanph cords and follicles is 

 dotted. In the later stages the increased number of the dots represents 

 the increase in lymphocytes and the lines show the beginning capsule 

 and trabecule. 



