THE CELL-DOCTRINE OF PHYSIOLOGY. 137 



in the posterior layer of the cornea, capsule of the lens, sarco- 

 lemma of muscle, &c. 



2. Simple fibrous tissues, including the white and yellow 

 fibrous tissues, and the areolar tissue, which is formed from 



Fig. 42. 



them. Henle believes the white fibrous tissue to be formed by 

 cells ; the yellow, by nuclei. 



3. Simple cells, floating separately and freely in the fluids, 

 as corpuscles of the blood, lymph, and chyle. 



4. Simple cells developed on the free surfaces of the body, 

 as epidermis and epithelium. 



5. Compound membranes ; composed of simple membrane, 

 and a layer of cells, of various forms (epithelium and epidermis) ; 

 or of aretlar tissue and epithelium ; as mucous membrane, skin, 

 secreting glands, serous and synovial membranes. 



12* 



