244 The Control of Salivary Secretion 



in the hypothalamus of cats ; on electrical stimulation a picture of 

 intense emotional excitement was obtained and after stimulation 

 for one minute or more saliva was observed to run from the mouth. 

 Similar observations were reported by Masserman (1937, 1938, 

 19390, I 94 1 )- Other symptoms were found in these experiments, 

 which do not seem to belong to the pseudo-affective reaction, such 

 as licking movements of the tongue and jaws. 



The investigations by Hess and his associates throw further light 

 on such findings and give a very interesting picture of salivation as 

 participating in various physiological mechanisms for which there 

 is evidence to show that the diencephalon serves as an integrative 

 area (Hess and Magnus, 1943; Baum, 1945; Hess, 1948, 1949). 

 Stimulation of certain regions in the waking cat resulted in secretion 

 of saliva, combined with movements of the lips and tongue, and 

 chewing and swallowing; the picture was that of an eating cat. 

 Responses from other areas were those of a cat trying to rid itself 

 of an objectionable substance: a special type of licking, salivation, 

 retching and vomiting. Another group of symptoms bring the 

 thermoregulatory function of the hypothalamus to mind. In cats 

 and dogs where sweat glands occur only over a very small area of 

 skin, removal of heat by evaporation of water depends mainly on 

 a free flow of saliva over the tongue, and a rapid passage of air over 

 these surfaces through panting. In the experiments referred to, 

 stimulation produced a widely opened mouth with the tongue pro- 

 truded, rapid and shallow respiration, and saliva dripping from the 

 mouth. Finally, defence reactions, similar to those described by 

 Bard, Ranson et al. and Masserman, were initiated from certain 

 regions. For a closer anatomical localization of the different groups 

 of symptoms studied, the papers and monographs by Hess and his 

 co-workers, including the topographical atlas by Hess (1956), 

 should be consulted. 



Chemical agents, injected into the hypothalamus, may produce 

 the same symptoms as electrical stimulation. Masserman (1938, 

 19396, 1941) injected strychnine, metrazol and picrotoxin into the 

 hypothalamus through a needle that was also used for electrical 

 stimulation, and obtained the symptoms of the sham rage reaction 

 although they were more prolonged than when electrical current 

 was used for excitation ; among the symptoms mentioned is saliva- 

 tion. As described in Chapter IV, numerous drugs may induce a 

 secretion of saliva when introduced into the ventricular system of 



