NERVES OF THYROID AND PARATHYROID BODIES 97 



The presence or absence of a definite basement membrane around 

 the follicles is an important point in regard to nerve and cell 

 relations. The majority of investigators are of the option that 

 a definitely formed basement membrane is absent, but that there 

 is a condensation of the connective tissue immediately surround- 

 ing the follicles, and this gives support to the bases of the epithelial 

 cells (Baber). 



The final endings of the nerves are short, fine, very varicosed 

 fibrillae which lie in this condensed connective tissue (figs. 1 and 

 4) . Some of these end fibrillae are curved, as described by Berke- 

 ley, while others are straight, and still others, and perhaps a 

 majority, are irregular. They always end in a knob-like enlarge- 

 ment on the basal ends of the cells; each cell, however, does not 

 come into relation with the end of a nerve, but only a few scat- 

 tered here and there throughout the follicles. I have been unable, 

 by most carefully examining a large number of sections with the 

 best magnification obtainable, to see any of these endings either 

 entering the cells or penetrating into their intercellular substance. 



In some of the literature concerning the nerve supply of the 

 thyroid the statement is made that ganglion cells were found in 

 different locations within the gland. Anderson and Berkeley, 

 however, with whom I agree, state that these structures are not 

 present. There are, in many of the sections stained by the chrome- 

 silver method, numbers of black precipitations which resemble 

 ganglion cells very closely in size and shape and could easily be 

 mistaken for them. A careful examination of many of these does 

 not reveal anything resembling a nucleus or nucleolus, while even 

 if nerve fibers enter them, the arrangement is not characteristic 

 of ganglion cell processes. 



THE NERVES OF THE PARATHYROID 



A careful examination of all the literature accessible concern- 

 ing the parathyroid has failed to reveal any reference whatever 

 to its nerve supply, and one of the latest histologies makes the 

 statement that this subject needs further investigation. 



The technique used in investigating the nerves of the parathy- 

 roid was the double impregnation method of Cajal as given in 



