2/6 PHYSIOLOGY. 



neously attributed to the lungs or kidneys. Hence there 

 is frequently a wholly needless apprehension of deep- 

 seated disorder, whereas in reality there is merely a strain 

 of superficial muscles. In amputating a limb the chief 

 pain is in cutting through the skin. Some excellent 

 authorities still hold the view that pain is merely the 

 result of intensifying any of the simple sensations ; but it 

 is generally held that it results from the excessive stimula- 

 tion of the nerves of general sensibility ; as Foster puts it, 

 " the constantly smouldering embers of common sensibility 

 may be at any moment fanned into the flame of pain." 



Pain a General Sense. In the real "special senses," 



sight, hearing, smell, taste, touch, and temperature sense, 



we refer the sensation to some external object, whereas 

 general sensations are subjective, referred to our bodies. 

 Ordinarily we do not localize the common sensations, and 

 a further indication of the relationship of pain and general 

 sensation is in the lack of complete localization of pain. 

 Slight pain, especially in the skin, may be closely located, 

 but severe pain tends to become indefinite and diffuse. 

 So we may class both the muscular sense and pain with 

 the "general" rather than with the "special" senses. 



Hunger and Thirst. The cause of these sensations in 

 a healthy body is plainly the need of food and water 

 throughout the system generally. The sensation of thirst 

 manifests itself in the throat, and the longing may be tem- 

 porarily relieved by merely moistening the throat. So 

 hunger may, for the time, be appeased by filling the stom- 

 ach with indigestible material. But the sensation soon 

 returns. The system has a crying need, and it is not to be 

 put off by any such frauds. That these sensations are 

 really demands made by the body as a whole may be 



