GEA Pa Eke ae 
THE ENLARGEMENT OF PARTS FROM INCREASED USE, 
OVERGROWTH, AND IRRITATION. 
Ir is well established that the increased use of a part 
tends to enlarge and strengthen it, that disuse on the other 
hand often leads to its diminution and enfeeblement: 
structural modifications thus induced are inherited. 
The truth of the first part of this statement may be 
demonstrated by a simple experiment : Let the arm of a 
healthy person be firmly strapped for several consecutive 
days upon a splint—in a few days the muscles will be 
softer than usual and actual measurements will show 
that the limb has diminished in size. Allow the arm to 
resume its function; the lost ground will be quickly 
recovered. 
When a young and vigorous person has the mis- 
fortune to lose an arm the remaining limb, being used 
for all purposes, will rapidly increase in size and strength. 
The same facts may be observed in dogs and cats which 
have lost a limb or part of a limb. A woman, aged fifty, 
had her big toe, including the metatarsal bone, ampu- 
tated ; six months after she had regained the use of the 
foot, the second toe had enlarged, and stood out from its 
fellows in such a way as to resemble in size and general 
appearance the lost toe—indeed, when the foot was 
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