REVIEW. 475 
of puberty and not till then, and that on the chin and upper lip of the male 
sex only, sets our ingenuity at defiance/ 
“ It is also observed by Mason Good, in treating of this subject, that the 
* roots or bulbs/ of hairs, ‘ are found over the whole surface of the body, 
though they only vegetate in particular parts, for which it is not easy to assign 
a reason / ” 
The deposition of fat , is considered by our author, to be 
an evidence of diminished nervous energy, and accompanied 
with a state of the blood implying inferior vital conditions. 
Moreover, it is antagonistic to the vigorous growth of hair, 
both in man and the lower animals ; these latter, having a 
variety of supplementary organs, originating in causes dif- 
fering only in degree from those which give rise to the 
growth of hair in the former. 
Passing over much that is interesting respecting the struc- 
ture and function of the skin, we come to the 6e causes of the 
development of particular hairy appendages in the higher classes 
of quadrupeds 
“We shall examine the growth of hair in the several regions of the horse. 
The supplementary structures by which he is distinguished, are familiar to 
every one. We may observe, previously to entering upon the task, that the 
facts and reasoning adduced on this occasion, will apply with equal force to 
analogous productions in other animals. The examples we shall bring under 
consideration will necessarily be few, but sufficient to illustrate and confirm 
the accuracy of the views^ brought forward. 
The hair on the face and lateral parts of the neck, in the horse, does not 
grow to the same extent as on the general surface of the body. The move- 
ments of the animal do not affect the former in the same degree as the 
latter; and according to the vigour of the vital actions, in the several cu~ 
taneous regions, supposing other things to be equal, is the amount of the 
external appendage. We have here ihe manifestation of cause and effect, 
the latter varying in strict correspondence with the modifications of the 
former. 
“ One of the most striking and ornamental features of the horse is the 
mane, which is common to both sexes. It is, however, much more exube- 
rant in the male than female, showing that, in the former, the functions of 
life are characterised by greater energy, from the influence of the gene- 
rative system. Hence agreeably to the difference, is the amount of 
elements to be emitted from particular localities of the body in the con- 
dition of hair. 
“ The mane extends from the upper part of the head to the beginning of 
the shoulders, and in the entire horse grows to a great length. Why it 
should be confined to this limited space we shall endeavour to explain. 
The circumscribed development of it agrees with the anatomy of the parts 
and the distribution of nervous power. The dorsal and lumbar portions of 
the spinal marrow find an issue for their nerves, and the expenditure of 
their power, in three directions. 
“ 1st. They communicate with the sympathetic in the abdomen, impart- 
