466 NORMAL HISTOLOGY AND ORGANOGRAPHY. 



4. Brown connective-tissue pigment cells may be 

 scraped from the choroid coat of the eye after re- 

 moving the retina. 



5. Sections and teased preparations of ligamentum 

 tiuchae of the ox. 



6. Sections and teased preparations of a tendon. 



7. Elastic fibers of the mesentery of a rat. 



PREPARATION OF ELASTIC FIBERS. 



(1) Fill abdominal cavity of a rat with 95 per cent, 

 alcohol, one hour. 



(2) Remove intestine with mesentery attached 

 and place in fresh alcohol. 



(3) Cut away the mesentery and mordant with 

 6 per cent, solution of boric acid. 



(4) Stain. 



Orcein 1 part. 



Alcohol, 95 per cent 100 parts. 



Hydrochloric acid 1 part 



Stain for one to twelve hours. The fibers should 

 appear dark brown. If stained too deeply, treat 

 with acid alcohol, J per cent, hydrochloric acid. If 

 too red, dip the pieces in fifty per cent, alcohol satu- 

 rated with ammonium picrate. 



Cartilage. 



1 . Cartilage sections may be cut with a razor from 

 bone joints obtained at a meat market. 



2. Sections of trachea for hyaline variety. The 

 sections must be cut thin and not overstained. 



Bone. 



i. Ground sections, mounted dry. A dry white 

 and fat-free bone is the best. With a turning table 

 ring a glass slide with balsam. Before the balsam 



