412 



THE ORGANS 



scribed. It is probable that the dear cells represent the resting, the 

 granular cells the active secreting condition of the same cell. 



The parathyreoids originate as epithelial cv aginations from the third and 

 fourth branchial grooves, and develop wholly independently of the thyreoid. 



The powerful influence which these minute organs exert is shown both clinically 

 and experimentally. Fatal tetany, resulting from the earlier operations for 

 complete removal of the thyreoids, has been shown by animal experimentation 

 to be due not to the removal of the thyreoids, but to coincident removal of the 

 parathyreoids, the removal of the latter only, in animals, giving the same results.' 



Fig. 291. — Section of Human Parathyreoid, showing lumina indicating tubular or 



tubulo-alveolar structure. (Pool.) 



TECHNIC 



The thyreoid and parathyreoid glands are best fixed in formalin-MuUer's fluid. 

 Sections may be stained with haematoxylin-eosin or hajmatoxylin-picro-acid- 

 fuchsin and mounted in balsam. 



General Reference for Further Study 



Pool: Tetany Parathyreopriva. Annals of Surgery, October, 1907. 



' For much of the description of the parathyreoids and for the photograph the 

 writer is indebted to Dr. Eugene H. Pool. 



