692 THE MICROSCOPE. 



reparation of the framework, or growth that incessantly 

 goes on in the animal body. 



Classification of the Animal Tissues. Professor Schwann 

 classifies the fundamental tissues of the human body as 

 follows : and it will be seen that more than half are 

 made up of cellular tissue or simple membrane. 



1. Simple membrane : employed alone \ Examples : Walls of cells, capsule of 

 in the formation of compound > lens of the eye, sarcolemma of 

 membranes ; muscle, <fcc. 



} Examples : White and yellow fibrous 

 tissue, areola tissue, elastic tissue, 



3. Cellular tissues jAljn^J.ijj.vg 



4. Sclerous, calcareous, or hard tissues j 



5. Compound membranes : composed -\ 



of simple membrane and a layer of / Examples : Mucous membrane, skin, 

 cells of various forms (ephithelium > true or secreting glands, serous and 

 or epidermis), or of areola or con- V synovial membranes. 

 nective tissue and epithelium . . J 



6. Compound tissues; a, those com-\ 



substance ......... ) 



fll>ro 8 



Cellular or Formative Membrane. Areolar or connective 

 tissue is generally distributed throughout the body, and 



various forms of this tissue are 

 found ; it is seen uniting to- 

 gether component parts, tilling 

 up interstices between them, 

 and affording a support to the 

 blood-vessels and nerves, be- 

 fore they are distributed to the 

 various organs. This tissue is 

 soft, clear, smooth, and ex- 

 tremely minute, being the 

 1-1 2,000th of an inch in dia- 

 meter, sometimes less. The 

 fibre is usually found united 

 together in bundles; if 



Fig. 321. Fibrous tissue, lining the in- these be acted Upon by dilute 

 terior of the eggshell, the lime having ,. -, .1 *i 



beenpreviouslyremovedby immersion acetlC acid, they Swell Up, 



in dilute hydrochloric M id. become transparent, and the 



appearance of fibrous structure is no longer seen, although 



