70 ANATOMY. 



Amphibia. 



Average size in parts of an inch. 



Frog (length), . . . . . . . . V. WOIF to 1200 



Siren (length), . . . . . ., ....-,.... . ^ 



Proteus (length), . '..'..,. .. "' '"-..%/ ' Cj, - ss<j 



Fishes. 

 Various species (length), . -. .,^- -r^:- ,,,-, riVj to s*W 



SPECIFIC GRAVITY or CERTAIN ANIMAL FLUIDS AND TISSUES, WATER 

 BEING 1000 DEGREES. 



Chyle, ,- ''. . 1024 



Lymph, . . . . . . *P*> v .. . . 1037 



Blood, :. ' 1052 to 1057 



" Serum, .- . 1028 



" Ked corpuscles, >i . 1088 



Adipose tissue, .<' 932 



Brain substance (white), 1009 



(gray), 1(530 



Muscular tissue, . . 1020 



Cartilage, 1150 



Bone, 1870 to 1970 



The entire body, 1065 



The specific gravity of the glandular organs and their secretions is given 

 with the descriptions of those parts and fluids. 



THE PHYSICAL PROPERTIES OF THE TISSUES. 



lit is scarcely necessary to state here, that the materials of the body 

 have all the physical properties of matter generally, such as weight, 

 cohesion, extensibility, inertia, impenetrability, and so forth. Speci- 

 ally, however, we have to notice that, with the exception of the extreme 

 outer layer of the cuticle, and the hairs and nails, every part and 

 tissue of the body is moist. Even those parts contain a small quantity 

 of water. With the above-mentioned partial exceptions, all the tis- 

 sues are exceedingly permeable to that element or to solutions of which 

 water is the main constituent ; and when dried, as may be exemplified 

 in the case of a piece of dried flesh, tendon or bladder, they very 

 greedily reabsorb their lost quantity of fluid, when placed in circum- 

 stances in which they can do so. 



The physical characters of all the animal tissues, indeed, are largely, 

 nay, essentially, dependent on the presence of the water contained, 

 not only in the fluids or intermediate moist blastema, but also in the 

 very substance of the more consistent tissues. Thus it is their con- 

 tained or essential water which endows all the soft textures, mem- 

 branes, and organs with the requisite suppleness, flexibility, and general 

 elasticity or resiliency ; whilst their relative mobility amongst or over 

 each other, is secured by their different degrees of softness, and by 

 the presence of the intermediate moisture. The toughness or cohesive- 

 ness of all the consistent tissues, even of bone itself, also demands a 

 certain proportion of combined or constituent water; Finally, the 

 special or peculiar India-rubber like elasticity possessed, and exhibited, 





