ROLE OF THE PROSENCEPHALON IN SHIVERING 
This suggests that the anterior hypothalamus migjit suppress 
shivering and depress the posterior hypothalamic neurons which 
activate the tremor by separate neural pathways. However, we will 
need additional experimental evidence in order to defend this 
concept. 
In a previous paper from our laboratory, Birzis and Hemingway 
(1957) reported that shivering was best produced with stimuli of 
25 pulses/sec and best suppressed with stimuli of 200 pulses/sec. 
They cited no experimental results and their concept is in conflict 
with the results shown in Figures 6 and 25 and the discussion fol- 
lowing a recent paper by McLean (1959), all of which surest the 
optimal stimulus frequency to be about 50 pulses /sec for septal 
effector mechanisms. 
Time does not permit an adequate recognition of the work of 
Heath (1953) and McLean (1959), who have illustrated the variety 
of vegetative and psychological phenomena influenced by the septum. 
The experiments reported here are but an isolated aspect of septal 
modualtion of hypothalamus functions. 
THE EFFECTS OF SEPTAL LESIONS ON SHIVERING 
Methods . Bilateral septal lesions were made in 14 cats. The 
surgical and postoperative nursingtechniques involved we re similar 
to those outlined above. 
One animal died 6 days, one 9 days, one 10 days and one 34 
days after operation. This last animal appeared normal in all re- 
spects except for his refusal to eat spontaneously and his habit of 
vomiting all force-fed feed. At the time of death, his weigjit was 
only 58 percent of the pre-surgery level. 
The remaining ten animals were given cold stress tests, 
sacrificed, and their brains fixed, sectioned, and stained as de- 
scribed above. 
375 
