134 DOMESTICATED ANIMALS AND PLANTS 
The ostrich is losing his useless wings, and those of the 
apteryx have gone, except that some of the bones can yet be 
found just under the skin of the breast. And so examples of 
missing or disappearing parts could be multiplied indefinitely, 
but enough have been given to show that development does not 
always proceed regularly, and that the arrest of one part does 
not necessarily prevent the development of others. 
The most important phase of this subject to the general 
student is in the field of the mental and moral characters, espe- 
cially with people. Idiocy is but the arrested development of 
one or all of the mental faculties, just as insanity is their break- 
ing down from insufficient power originally or from overwork 
or abuse in life. 
Just as we have idiotic people, so we have idiots among 
horses and dogs, a fact that destroys or greatly lessens their 
value in proportion to the kind of work we expect them to do. 
We have also insane individuals in both species, and some of 
the most dangerous runaways are due to sudden insanity of the 
horse, brought on by fright, old age, or disease. 
Both horsemen and dog fanciers should understand that in 
these two species we are dealing with mental faculties of an 
order so high that any disturbance or shortage is a serious 
matter. Other animals are of a much lower order of mentality 
and we depend less upon their intelligence, so that relative 
idiocy is not so noticeable, nor is insanity so likely to appear, 
because they lead, upon the whole, a relatively tranquil life. 
Occasionally, however, a steer loses his head, as when being 
driven in a strange place, and when he does it is a good time 
to find cover.! 
The most serious consequences follow the arrested develop- 
ment of the mental and moral faculties in man. We are only 
recently coming to recognize these unfortunate individuals as 
degenerates and to realize their wholly dangerous character. A 
1 This happens frequently about the stockyards in all markets, though 
commonly animals in large numbers are extremely quiet. 
