36 



COMPARATIVE ZOOLOGY. 



are condensed into sheets or parallel cords, having a wavy, 

 glistening appearance. Such strnctures are the fasciae and 

 tendons. Connective tissue is not very sensitive. It con- 

 tains gelatin — the matter virhich tans when hide is made 

 into leather. In this tissue the intercellular substances 

 take tlie form of fibres. The white fibres are inelas- 

 tic, and from ^rrinr to -^^^o of an inch in diameter. 

 They are best seen in the tendons. The yellow fibres are 

 elastic, curled at the ends, very long, 

 a,nd from -^xhirs to -^-^-s of an inch in 

 diameter. They are shown in the 

 hinge-ligament of an Oyster. Connec- 

 tive tissue appears areolai-, *'. e., shows 

 interspaces, only under the microscope. 

 (3) Cartilaginous Tissue. — This tissue, 

 known also as "gristle," is composed, 

 of cells imbedded in a granular or hy- 



Fiu. 6. — Hyaline Car-tihige, 

 Diagram : a, cartilage 

 cell \ 6, cell about to di- 

 vide ; c, cell divided iuto 

 two; d, into foiir parts. 

 The space between the 



cells is fliied with trans- aline substance, which is dense, elastic, 



parent intercellular sub- ' ' ' 



stance; highly miigni- bluish - white, and trausluceut. 



fled. ' 



It is 

 found where strength, elasticity, add 

 insensibility are wanted, as at the 

 joints. It also takes the place of the 

 long bones in the embryo. "When 

 cartilage is mixed with connective tis- 

 sue, as in the ear, it is called Jihro-car- 

 tilage. 



(4) Osseous Tissue. — This hard, opaque 

 tissue, called " bone," differs fi-om the 

 former two in having the intercellular 

 spaces or meshes filled with phosphate 

 of lime and other earths, instead of a 

 hyaline or fibrous substance. It may 

 ''i:/erx%';"«:faruiag; ^6 Called petrified tissuc-thc quantity 

 cells passing into com- of earthy matter, and therefore the brit- 



pact boue, c, and then 



spongy bone, e. tleness of the bone, increasing with the 



