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The Rate of Animal Development. 
[April, 
IV. THE RATE OF ANIMAL DEVELOPMENT. 
By J. W. Slater. 
“ Consider young ducks.” 
t NE of the attempts which have been made to establish 
the existence of a “ great gulf” between man and 
beast may be pronounced exceptionally curious as an 
instance alike of careless and defective observation and of 
rash conclusions. That by such arguments men of eminence 
could really mislead themselves, and succeed for a length of 
time in misleading the outside public, is deeply humiliating. 
Prof. St. George Mivart suggests* that a book should be 
written on the “ stupidity of animals.” We are far from 
denying that such a work would be useful ; but should the 
needful companion volume on the “ stupidity of man make 
its appearance in due course, it might not unfittingly open 
with the reasoning we are about to quote. 
To begin then : the slow bodily development of the human 
infant and its prolonged helplessness are matters far too 
familiar to require proof, or even illustration. . No less 
familiar and universally admitted is the rapidity with which 
foals, calves, lambs, kids, chickens, and ducklings acquire the 
use of their limbs and other organs. These fafts could not 
fail to come under the notice even of the most careless 
observers. But who could have imagined that the said facets 
would be, without further enquiry, at once seized hold of as 
a theme for stilted declamation, and be elevated to the rank 
of a fundamental distinction between man and the lower 
animals. Yet this strange error has actually been com- 
mitted, not merely by men of words, like Addison, Paley, 
and Whewell, — which is surely sad enough,— but even by a 
man of things, like Sir Humphry Davy. The great chemist 
attempts to show that man does not use his limbs in- 
stinctively like other animals. Says he : — . 
“ Man is so constituted that his muscles acquire their 
power by habit, t but in the colt and the chicken the limbs 
are formed with the power of motion, and these animals 
walk as soon as they have quitted the womb or the egg. 
* Lessons from Nature. 
t To speak of acquiring a power by habit is scarcely rational, ihe power 
must exist before the habit can be formed. 
