246 Evolution and Adaptation 



out of all proportion to what we should expect on the theory. 

 And is it not a little odd that the end of the nose should be 

 so highly sensitive ? 



There is another point that we cannot afford to neglect in 

 this connection. It is known that in addition to touch-spots 

 there are warm and cold spots in the skin, which produce, 

 when touched, the sensation of warmth, or of cold, respec- 

 tively, and not the sensation of touch. The degree of 

 sensitiveness of different regions of the body throws an 

 interesting side-light on Spencer's argument. 



The warm spots are much fewer than the cold spots. The 

 spots are arranged in short lines radiating from centres 

 which coincide with hairs. The number of these spots 

 varies a good deal, even in the same region of the skin. If 

 the sensitiveness of the skin is tested, the following results 

 will be obtained. The list includes twelve grades of sensitive- 

 ness, beginning with the places giving the lowest maximum 

 of intensity. About one hundred square areas were tested 

 in each region. 



COLD SENSATIONS 



i. Tips of fingers and toes, malleoli, ankle. 



2. Other parts of digits, tip of nose, olecranon. 



3. Glabella, chin, palm, gums. 



4. Occiput, patella, wrist. 



5. Clavicle, neck, forehead, tongue. 



6. Buttocks, upper eyelid. 



7. Lower eyelid, popliteal space, sole, cheek. 



8. Inner aspect of thigh, arm above elbow. 



9. The intercostal spaces along axillary line. 



10. Mammary areola. 



11. Nipple, flank. 



12. Certain areas of the loins and abdomen. 



WARMTH SENSATIONS 



0. Lower gum, mucosa of cheek, cornea. 



1. Tips of fingers and toes, cavity of mouth, conjunctiva, and 

 patella. 



