REVIEW. 
473 
variety or singularity, reciprocally throw light on the field of 
research, and on the circumstances modifying the appearance 
of external attributes.” 
We shall make our quotations almost at random from the 
work before us, inasmuch as these may provoke our readers 
to a perusal of it for themselves. Moreover, the author 
informs us that, ce though complete in itself, it contains only 
the first half of his researches concerning the supplementary 
organs of the animal kingdom. The other portion is equally 
ready for the press, but he withholds it on these grounds: 
if the principles advanced be true, it will scarcely be denied 
that they constitute an important step in physiology ; but if 
false, the fallacies are indeed of a grave character. Afraid of 
multiplying the latter, he adopts this course, whether wise or 
not it is for others to decide, of offering this part of his 
undertaking, in order to elicit the sentiments of impartial 
and competent authorities.” 
At the very outset Dr. Holland expresses himself as not 
being insensible to the difficulties that present themselves in 
his undertaking. “ The task,” he says, ec on which w r e enter 
is one of no ordinary kind. It has little in common w ith 
previous physiological investigations. We mention this not 
as a ground of merit, or to secure the indulgent consideration 
of the critic, but as an apology for the defects of which we 
are fully conscious. * * * * * For more than thirty years 
w r e have zealously cultivated physiological pursuits, and from 
no other motive than a desire to arrive at truth, and, if 
possible, to enlarge the boundaries of a science of vital 
importance to humanity.” He then goes on to consider the 
structure, uses, peculiarities, &c. of the appendages to the. 
animal, beginning with the hair. 
This, as a covering for the head, Dr. Holland does not 
consider as intended to protect it from external injuries, or 
to keep up its natural degree of heat. Were it so, he asks 
“ Why does it, after the prime of manhood, disappear to a 
great extent from this particular region. It decays, and 
leaves a smooth polished surface, w 7 hen clearly it is most 
urgently required for the purpose assigned to it.” Nor is it 
xxx. 63 
