286 REVIEW.—BRIDGEWATER TREATISES, NO. 9 . 
designation are included not merely the skin, but also all the 
parts that are immediately connected with it—are the immediate 
organs of the sense of touch. No parts of the animal structure 
present greater diversity in their form and outward appearance 
than the integuments; yet it is easy to discover, amidst all these 
varieties, that the same general plan has been followed in their 
construction, and that each particular formation is the result of 
the same elementary structures. Of these elements die most 
important, and that which generally composes the chief bulk of 
the skin, is the corium or true skin. The outermost layer is 
termed the epidermic cuticle or scarf-skin; and between these 
there is often found an intermediate layer, denominated the rete 
mucosum or the pymentum. 
The corium forms the principal portion of the skin, and is 
constructed of an intertexture of dense and tough fibres, through 
which a multitude of bloodvessels and nerves are interspersed ; 
but its external surface is more vascular than any other part, 
exhibiting a fine and delicate net-work of vessels; and it is this 
portion of the skin, termed by anatomists the vascular plexuSy 
which is the most acutely sensible in every point: hence, we may 
infer that it contains the terminations of all the nervous filaments 
distributed to this organ, and which are here found to divide to 
an extreme degree of minuteness.” 
The author describes the condition on which the perfection of 
the sense of touch depends in the various living beings that in¬ 
habit the sea, the earth, and air: his description is beautiful as 
it is interesting. Our limits prevent us from entering on this 
delightful study; we must, therefore, pass over this, together 
with the different chapters on taste, smell, hearing, and vision, 
merely remarking, en passant, that the author has plainly shewn 
that these different senses have been harmoniously and studiously 
adjusted, not only to the properties and the constitution of the 
material world, but also to the respective wants and necessities 
of each species in the situations and circumstances where it has 
been placed by the gracious and beneficent author of its being. 
The 8th chapter, on the comparative physiology of the 
nervous system,” is a very interesting one. Our knowledge of 
the exact uses and functions of the various parts which compose 
the nervous system, and especially of its central masses, is un¬ 
fortunately too scanty to enable us to discern the correspond¬ 
ence which undoubtedly exists between the variations in the 
functions and the diversities in the organization; yet the author 
has given us a clear view of the different plans according to 
which the nervous system is constructed in the several classes of 
animals, and shews distinctly that these central masses are mul¬ 
tiplied and developed in proportion as the faculties of the animal 
