PARS NEURALIS AND INTERNAL SECRETION 



sipidus, Biggart (1935-36) also observed changes in the su- 

 praoptic nuclei and stalk consistent with the views expressed 

 by Fisher, Ingram, and Ranson. There is little evidence to 



Fig. 27. — One position in which bilateral lesions of the hypothalamus can be 

 placed to produce diabetes insipidus in the cat by interrupting fibers of hypothala- 

 mic hypophysial tracts. (From Fisher, Ingram, and Ranson, Arch. Neurol. Psy- 

 chiat., 34, 124-63 [1935]-) 



./; pars glandularis; Ent: entopeduncular nucleus; Fil: filiform (paraventricu- 

 lar) nucleus; /; pars intermedia; L: lesion as stippled area; Mth: mammillothalamic 

 tract; OT: optic tract; P: pars neuralis; Perivetit: periventricular nucleus; PP: 

 pes peduncuh; St: stalk; T: pars tuberalis; Tang: caudal part of tangential (supra- 

 optic) nucleus; VM: ventromedial hypothalamic nucleus. 



favor Biggart's opinion that the pars tuberalis is etiologically 

 important in diabetes insipidus. There is still less justifica- 

 tion for his belief that diuresis inhibition by the vasopressor 

 principle depends to an important extent on an action of the 

 hormone on tuberal nuclei (in Biggart's Case 5 the polyuria 



f28il 



