ANATOMY OF THE PITUITARY BODY 



finding was confirmed in the guinea pig (Collin, 1932) but not 

 in other studies of human material ('Espinasse, 1933). 



The ?jerves of the pituitary body.^ — According to Dandy 

 (1913), the pars glandularis of the dog and cat is suppHed 

 with numerous sympathetic fibers arising from the carotid 

 plexus. Pines (1925) found that these fibers finally formed 

 intercellular plexuses from which arose pericellular nets ter- 

 minating in button-like thickenings on the surface of the cells 

 of the pars glandularis. Possibly of greater importance is the 

 large bundle of non-myelinated nerve fibers passing from the 

 hypothalamus down the stalk to be distributed to the pars 

 neuralis and pars intermedia (perhaps also to the pars tuber- 

 alis). The source of these fibers in the hypothalamus was 

 first investigated by Pines (1925), Stengel (1926), and par- 

 ticularly by Greving (1926, 1928, 1930). The cells of origin 

 are considered to be located in the nuclei paraventriculares 

 and, more clearly, in the nuclei supraoptici (see Fig. 5). 

 Both pairs of nuclei can be recognized in a number of mam- 

 mals (Griinthal, 1933). The axones pass down the stalk as a 

 bundle of non-myelinated fibers (tractus hypothalamo-hypo- 

 physius) terminating chiefly in the pars neuralis, but also 

 ending as fibrils, often thickened at the end, about or within 

 the cells of the pars intermedia (Roussy and Mosinger, 1933). 

 It has been argued by Greving, and by Roussy and Mosinger, 

 that these fibers regulate secretion in at least the pars neuralis 

 and the pars intermedia. The best physiologic evidence in 

 favor of this view has been obtained in the case of the pars 

 intermedia of cold-blooded animals like the frog. There is 

 very little evidence that secretory nerves control the activity 

 of the pars glandularis; most experiments designed to demon- 

 strate secretory nerves have either denied their existence or 

 have been inconclusive like those of Vogt (193 1). 



' For the older literature of Cajal's school, see the translation of Cajal's Histology 

 by Fernan-Nuiiez (Baltimore, 193J). 



[II] 



