100 NATURAL HISTORY. 
and of motion is that of the Monkeys which have well-formed thumbs. The notion of a useless 
organ is at first repulsive to our ideas of the benevolent scheme of Nature. Mr. Darwin writes, 
“ In reflecting on them every one must be struck with astonishment ; for the same reasoning power 
which tells us plainly that most parts and organs are exquisitely adapted for certain purposes tells us 
with equal plainness that these rudimentary or atrophied organs are imperfect or useless.” Let us 
take a well-known instance of such a structure : the Calf when born has cutting teeth in its upper jaw 
hidden in the gum ; they are not in sockets, and even if they were, they would be of no use in 
biting. The Ox has no cutting or incisor teeth in its upper jaw, as every one knows, and the tongue 
touches a hard and moist gum there. The incisor teeth of the Calf are never cut, but they are gradually 
absorbed in the gum with age. Now what is their meaning ’l They are of no use in sucking, or in 
combos tekus. (AJhr Vflt> LcnaJon.: 
anything which occurs in the early life of the animal : they are clearly useless and rudimentary or 
atrophied structures. Take another example : the little Kiwi bird of New Zealand has no wings with 
which to fly, yet the bones are there in a dwarfed and rudimentary condition ; many insects have no 
wings, or have them so reduced in size that they are of no use in flight, and sometimes the males have 
them in perfection, and the females have none. In explaining this subject two courses are open, first, 
to beg the question, and to say that the design of the Creator was thus ; or to account for it on the 
principle that the Creator acts by law, and that creatures become modified and altered by inherent 
power, and by having to obey the force of surrounding circumstances generation after generation. 
In the instance of the male and female insect just noticed, the male is active, and has to search for 
las partner, and the female is a stay-at-home, and expects to be courted, and when mated to do nothing 
more than lay eggs. Tier wings would be of doubtful value. "VN e may believe, then, that disuse. t 
generation after generation, gradually weakened the wing, and finally Nature, ever economical in not* 
used organs, did not perpetuate it. Disuse may he therefore considered as the principal cause of the 
atrophy, rudimentary condition, and of the final deficiency of structures. But disuse will not 
produce this in one generation, but in many, so it is necessary to look farther back into the ancestry of 
