372 



ANUHRSSON AM) O I HERS 



hypothalamus has thus been found to inhibit food intake and ehcit thirst 

 (Fig. 9). Cooling of the same region of the brain has to a certain extent 



o. 



ISO 



grrrrS 



• • 



Fig. 10. Effect of chronic preoptic cooling on alimentation in a goat. During 

 70 hr of central cooling, water intake was totally abolished for the first 40 hr. 

 Drinking remained reduced thereafter, the animal failing to make up its water 

 deficit (as indicated by hyperconcentration of plasma electrolytes) until after 

 stopping of preoptic cooling. During these periods of adipsia and hypodipsia, the 

 animal continued to eat normal amounts of hay, despite the persistence of a 

 marked core of hyperthermia (40.8 to 41.5°C). (From Andersson, Gale and 



Sundsten, 1962b.) 



the reverse effect. The food intake of the animals is generally not in- 

 creased but it remains at a normal level during long periods of anterior 

 hypothalamus cooling, even though there is a rise in the body temperature 

 to above 410. In the goat this is a critical temperature at which food 



