124 
ANIMAL PEDIGREES. 
June, 1891 . 
its legs, and its tail; the additions being cleverly effected 
so as to leave the original kitten unaltered in the middle, and 
fully exposed to view the whole time. 
The above examples, selected almost haphazard, will 
suffice to illustrate the Theory of Becapitulation. The proof 
of the theory depends chiefly on its universal applicability 
to all animals, whether high or low in the zoological scale, 
and to all their parts and organs. It derives also strong 
support from the ready explanation which it gives of many 
otherwise unintelligible points. 
Of these latter familiar and most instructive instances 
are afforded by rudimentary organs, i.e, structures which, 
like the outer digits of the horse’s leg, or the intrinsic muscles 
of the ear of a man, are present in the adult in an incom¬ 
pletely developed form, and in a condition in which they can 
be of no use to their possessors ; or else structures which are 
present in the embryo, but disappear completely before the 
adult condition is attained; for example, the teeth of 
whalebone whales or the gill-slits present in the neck during 
the embryonic phases of all higher vertebrates. 
Natural selection explains the preservation of useful 
variations, but will not account for the formation and per¬ 
petuation of useless organs, and rudiments such as those 
mentioned above would be unintelligible but for Becapitu¬ 
lation, which solves the problem at once, showing that these 
organs, though now useless, must have been of functional 
value to the ancestors of their present possessors, and that 
their appearance in the ontogeny of existing forms is due to 
repetition of ancestral characters. 
JL. 
Budimentary organs are extremely common, especially 
among the higher groups of animals, and their presence and 
significance are now well understood. Man himself affords 
numerous and excellent examples, not merely in his bodily 
structure, but by his speech, dress, and customs. For the 
silent letter b in the word “ doubt,” the g in “ foreign,” or 
the w of “ answer,” or the buttons on his elastic-side boots 
are as true examples of rudiments, unintelligible but for 
their past history, as are the ear muscles he possesses but 
cannot use; or the gill-clefts, which are functional in fishes 
and tadpoles, and are present, though useless, in the 
embryos of all higher vertebrates, which in their early 
stages the hare and the tortoise alike possess, and which are 
shared with them by cats and by kings. 
The fossil remains of animals and of plants yield results 
of the greatest importance when studied in the light of the 
Becapitulation Theory, I have thought it well to ask special 
attention to these, even at the risk of repeating what has been 
