92 



LECTURE VI. 



Formation of Tissue — Of EpUlielial and Fibrous Tis- 

 sue — Formation of Spiral Fibres — Contractile Tissue 

 — Nerve Tissue — Formation of Fihrous Tissue in 

 healing of a Wound — Simple Fihrous Connective 

 — Increase in Old Age and in Disease — Mode of in- 

 crease in Muscles and Nerves — No Fibrous Connec- 

 tive in Insects — Skeletons of young Organs in the 

 Adult — Interruption t, of Normal Changes — Vitreous 

 Humour — Mucous Tissue of Umbilical Cord — Con- 

 nective TisShie— White Fibrous Tissue — Repair- 

 Bioplasm of Cornea — Bioplasm of Yellow Elastic 

 Tissue — Ligament of the Nech of the Giraffe. 



The tissues of wbicli the internal organs of animals 

 are composed vary remarkably in structure, compo- 

 sition, and properties. We find varioiis gradations 

 of resistance and density, frora a texture of such ex- 

 treme tenuity as to be scarcely demonstrable, to the 

 firm, fibrous, cartilaginous, and osseous tissues, the 

 hardness of which renders their investigation difficult. 

 All tissues are, however, formed from masses of bio- 

 plasm ahke in general characters, though difiering 

 vastly in power. 



133. Formation of Eiiitlielial Tissue and Fibrous 

 Tissue. — By many the formation of structui-es like 

 epithehum has been looked upon as a process distinct 

 from that which results in the production of fibres. 

 In classifying the tissues, attempts have been made 

 to show that those textures which were composed of 

 multitudes of " cells," were of a different nature to 

 those which exhibited a "fibrous appearance." More 

 careful investigation has proved that these ideas must 



