ADIPOSE TISSUE. 
185 
used as a substitute for bear’s grease. From the whole 
of this tribe we procure a very firm fat known as tallow ; 
in the Pig it is still firmer, and called lard ; if a portion 
of either of these substances be cut transversely, the fat 
is so dense as to allow of the adipose cell being divided, 
and such tallow or lard is perfectly solid in all tem- 
peratures of this climate, and is capable of being em- 
ployed in the manufacture of candles. In the Turtle , 
there is under the carapace a quantity of adipose tissue 
contained within delicate areolse, formed principally of 
loose white fibrous tissue, and is well known as the 
green fat, being much prized by epicures. This fat is 
more digestible than that from ordinary animals, and 
I have frequently heard it remarked, that those persons 
who cannot easily digest the fat of beef or mutton, can 
consume large quantities of the fat in question without 
annoyance. 
I have stated, that the adipose tissue is supported by 
a fibrous net-work ; this holds good in the majority of 
cases, but, in the marrow of bones, no supporting tissue 
is present, and I here take the opportunity of demon- 
strating a point of some interest, which is of constant 
occurrence throughout the vertebrate kingdom, viz., that 
in the bones of the arm or leg, the marrow of the 
humerus and femur is exceedingly firm, whilst that of 
the lower part of the tibia or metatarsal bone is always 
more or less liquid, and it is from these bones that the 
ordinary neat’s foot oil is procured. The same thing is 
evident even in skeletons, in those of birds, it may be 
