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. 



Simple membrane : employed alone 

 in the formation of compound 

 membranes 



2. Fibrous tissues. 



3. Cellular tissues. 



4. Sclerous, calcareous, or hard tissues 



5. Compound membranes: composed - 



of simple membrane and a layer of 

 cells of various forms (ephithelium 

 or epidermis), or of areola or con- 

 nective tissue and epithelium . 



6. Compound tissues ; a, those com- 1 



posed of tubes of homogenous I 

 membrane, containing a peculiar i 



substance J 



b, those composed of white fibrous " 

 tissues and cartilage _ 



Examples : Walls of cells, capsule of 



lens of the eye, sarcolemma of 



muscle, <fec. 

 Examples : White and yellow fibrous 



tissue, areola tissue, elastic tissue, 



<fec. 

 Examples : Cartilage, fat, pigment, 



grey nervous matter, &c. 

 Examples : Rudimentary skeleton of 



invertebrata, bone, teeth, <fec. 



Examples : Mucous membrane, skin, 

 true or secreting glands, serous and 

 synovial membranes. 



Examples : Muscle, nerve. 



Example : Fibro-cartilage. 



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, rilling 

 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- 

 $C tremely minute, being the 

 l-12,000th of an inch in dia- 

 meter, sometimes less. The 

 fibre is usually found united 

 together in bundles ; if 

 Fig. 32i.— Fibrous tissue, lining th* in- these be acted upon by dilute 



tenor of the eggshell, the lime having ,. .-i .■• -,-, 



been previously removed by immersion acetlC aClQ, tUey Swell lip, 



in dilute hydrochloric acid. become transparent, and the 



appearance of fibrous structure is no longer seen, although 



