CHAP. ii. j THE BRAIN. 817 



the action of the brain as regards them seems limited to aug- 

 menting or inhibiting the activity of spinal centres. We should 

 therefore hardly expect them to be specially represented in the 

 cortical motor region. But emotions have a much wider and 

 more powerful influence over the splanchnic functions than has 

 the will, and have the power of affecting the work of certain 

 organs, for instance the heart and secreting glands, which the 

 will is unable to touch. And since we have every reason to 

 believe that the cortex is closely associated with the emotions, 

 we may naturally infer that the elements of the cortex supply 

 a link in the chain through which an emotion influences this or 

 that splanchnic activity; we may, accordingly, expect to find 

 that stimulation of some part or other of the cortex produces 

 splanchnic effects. The results of experimental investigation, 

 however, are both scanty and discordant; but the greater 

 weight should perhaps be attached to the positive results. 

 Thus, some observers find that stimulation of the cortex, the 

 locality being in the dog some part of the sigmoid gyrus, pro- 

 duces movements of the bladder; and they trace the path of 

 this influence through the front part of the thalamus and the 

 tegmentum to the bulb and so to the cord, excluding the cere- 

 bellum, which other observers believed to be concerned in the 

 matter. Some observers again find that stimulation of the cor- 

 tex produces a flow of ' chorda saliva,' while others maintain 

 that the secretion, when it does occur, is an indirect and not a 

 direct effect of the cortical stimulation ; and it may be remarked 

 that the cortical area, which is claimed to be a 'salivation 

 area,' lying in the dog on the convolutions dorsal to and in 

 front of the Sylvian fissure, is not either the area connected 

 with the facial nerve, or that allotted to taste or smell. 



Similarly, stimulation of parts of the cortex has in the hands 

 of various observers led to movements or to arrest- of movements 

 of the intestines, to changes in the beat of the heart, and to 

 various vaso-motor and other effects ; but it will not be profit- 

 able to enter into any further details. We may, however, add 

 the remark that when the cortical motor area for a limb is 

 removed, or suffers a lesion, the temporary paralysis which is 

 thereby caused is accompanied by a rise of temperature in the 

 limb ; this may be at times very great indeed ; in the monkey 

 for instance, the hand or foot on the paralysed side may be as 

 much as 5 C. higher than that of the other side. The effect is 

 partly due to vaso-motor paralysis, but, especially considering 

 that the muscles of the limb are relatively quiescent and so pro- 

 ducing less heat than usual, cannot be due to that alone. The 

 remarkable result may be taken as still further illustrating the 

 complexity of the processes connected with the cortical motor 

 area ; the area is in some way associated with the vascular 

 arrangements and nutrition of the muscles with whose move- 



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