186 



JEREMIAH S. FERGUSON 



his statement b}^ the use of itahcs. I can confirm that portion of 

 Baber's statement which says that an extensive system of vessels 

 within the thyroid gland can be readily injected bj^ the method of 

 puncture, but I would maintain that neither that procedure, nor 

 the injection of the dorsal aorta or efferent branchial vessels 

 with Berlin blue, would demonstrate the absence of lymphatics; 

 that they may still be present, I have demonstrated both in micro- 

 scopical sections and by injection (figs. 9, 10 and 11). 



Fig. 9. Lymphatics, "vasa lymphatica," and veins, "venae lymphaticae," 

 of the thyroid gland. The "vasa lymphatica" have been injected with ink and 

 the thyroid gland cleared and mounted in toto; the lumen of the follicle and the 

 follicular epithelium are only indistinctly seen. At X in the specimen the two 

 sets of vessels anastomose. 



Injection by puncture does not always fill the extensive system 

 of vessels observed by Baber. If one takes care to use only a very 

 gentle pressure, this system, which completely surrounds each 

 vesicle, is only filled near the point of injection, while at the mar- 

 gins of the injected area the fluid spreads through more minute 

 vessels which lie in closer contact with the vesicular epithelium 

 (fig. 9, L) . I believe these last are true vasa lymphatica in the sense 



