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 ' 

 in the formation of compound 

 membranes . . . 



2. Fibrous tissues. 



3. Cellular tissues. 



4. Sclerous, calcareous, or hard tissues | 



5. Compound membranes : composed -N 



of simple membrane and a layer of I 

 cells of various forms (ephithelium > 

 or epidermis), or of areola or con- \ 

 nective tissue and epithelium . . J 



6. Compound tissues ; a, those com- \ 



posed of tubes of homogenous ^ 

 membrane, containing a peculiars 



substance / 



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, 



&c. 

 Examples : Cartilage, fat, pigment, 



grey nervous matter, &c. 

 Examples : Rudimentary skeleton of 



invertebrata, bone, teeth, &c. 



Examples : Mucous membrane, skin, 

 true or secreting glands, serous and 

 synovial membranes. 



Examples : Muscle, nerve. 

 Example : Fibro-cartilage. 



Cellular or Formative Tissue. Areolar or connective 

 tissue is generally distributed throughout the body, and 



various forms of this tissue an 

 found ; it is seen uniting to- 

 gether component parts, filling 

 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. 32i. Fibrous tissue, lining the in- these be acted upon by dilute 

 S&EUijS[ acetic acid, they swell up, 

 in dilute hydrochloric acid. become transparent, and the 



appearance of fibrous structure is no longer seen, although 



