42 



FOURTH LECTURE. 



The connective-substance group, occurring throughout, 

 forms a large part of our body, the general frame-work, in 

 which the other tissues are embedded. They have rightly 

 been called the scaffold and supporting substance of the 

 body. 



Let us now examine their individual varieties. 

 Cartilage tissue makes its appearance very early in the con- 

 struction of the body, though frequently to disappear after a 

 short duration of life. Most cartilage, accordingly, does not 

 become old. Even at the hour of birth a considerable por- 

 tion of the cartilage has fallen a sacrifice to a new secondary 

 tissue, the osteoid or bone tissue. A portion of the cartilage 

 lasts, however, till the death of the person, and may thus 

 reach a great age. 



The texture is distinguished, according to several varieties 

 of the mature tissue, into : a, the hyaline ; b, the elastic ; c, 

 a rather uncertain variety, the connective-tissue cartilage, an 

 intermediate thing between cartilage and connective tissue. 



In its first embryonic appearance, the progressing cartilage 

 presents small spherical protoplasmic formative cells with 

 vesicular nuclei and rather scanty homogeneous intermediate 

 substance. The latter is still soft, and consists of albuminous 

 matter. Soon, however, the cells increase in size ; the inter- 

 mediate substance is augmented, and becomes more firm (Fig. 



23). A chemical change also takes 

 place gradually ; it becomes a gelat- 

 inous tissue ; on boiling, it yields 

 chondrine. 



When the intercellular substance 

 retains its original homogeneous 

 character, it forms hyaline cartilage. 

 Thin sections appear transparent like 

 glass. The cells (Fig. 42) have also, 

 in the mean time, assumed quite a 

 variation in their appearance. 



They appear larger, round, oval, 

 wedge-shaped. A portion of them show capsules, and not 



Fig. 42. — Diagram of a perfectly 

 mature hyaline curtilage, with quite 

 a variety of cells. 



