36 COMPARATIVE ZOOLOGY. 
a wavy, glistening appearance. Connective tissue is not 
very sensitive. It contains gelatine —the matter which 
tans when hide is made into leather.”* 
(3) Adipose Tissue.— This is simply an aggregation of 
large cells (averaging ;$5 Inch in diameter) filled with 
fat. They are distributed through the 
connective tissue (as in the “ blubber” 
of Whales), or united into distinet 
masses (as about the kidneys in Rn- 
minants). The marrow of bones is a 
good examiple. Globules of fat occur 
in many Molluscs and Insects; but 
true adipose tissue is found only in 
back- boned animals, particularly the 
OSs herbivorous. In the average Man, it 
Fre hin, of connecive Constitutes about =; part of his weight, 
pasue, - and a single Whale has yielded 120 
tons of oil. The fat of animals has the different names of 
oil, lard, tallow, suet, spermaceti, etc. It is a reserve of 
nutriment in excess of consumption, 
serving also as a packing material, and 
3a 
Ss 
a 
a 
‘as a protection against cold. 
(4) Cartilaginous Tissue.— This is a 
deep-seated structure, better known as 
“oristle,’ which is dense, elastic, blu- 
ish white, and translucent, composed of 
cells imbedded in a granular or hyaline 
substance. It is found where strength, 
elasticity, and insensibility are wanted, 
as at the joints. It also takes the place 
of bones in the embryo. When carti- 
lage is mixed with connective tissue, as 
in the ear, it is called fibro-cartilage. 7M io, eautilage 
(5) Osseous Tissue—This hard, opaque _ ¢ells, passing into com- 
: F pact bone, c, and then 
tissue, called “bone,” differs from the — spongy bone, e. 
