HOW THE BRAIN THINKS 



most part extremely minute, though some attain a 

 length of two or three feet. These units, for lack 

 of a more misleading name, are called cells. The 

 "cells" which run from the small of your back 

 down into your toes, and wiggle the same, or in- 

 form you when a member of the family is stubbed, 

 are the longest. Those of the brain are mostly so 

 small as to tax the powers of the microscope ; their 

 average length would be measured in thousandths 

 of an inch. There have been many attempts to 

 get at their actual number; it is certainly large. 

 Computations, for the brain alone, range from six 

 hundred millions upward. One, due, I think, to 

 Waldeyer, sets the total number of brain-cells 

 (average) at one thousand six hundred millions. 

 This would mean a brain population exceeding the 

 known population of the earth. 



Of course, the number varies enormously, for the 

 size and weight of the normal brain varies greatly. 

 A great deal of nonsense has been written on this 

 subject, and attempts made to trace a connection 

 between size and capability. This is obviously ab- 

 surd, for some of the largest brains known belonged 

 to idiots. The sizes of comparatively few distin- 

 guished brains are known, and most published fig- 

 ures are worthless. The list on the following page 

 is authoritative, and speaks for itself. The sizes 

 are given in cubic centimetres: 

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