1 6 PRACTICAL HISTOLOGY. 



drop of solution of strong carmine (p. xliii). Within a few minutes it will be stained of a 

 uniform deep red colour. Wash away the surplus carmine, and if the preparation is now ex- 

 amined (L) it will be of a nearly uniform red colour, the matrix scarcely distinguishable from 

 the corpuscles in the depth of the tint. Place on the section a large drop of a five per cent, 

 solution of glacial acetic acid for several minutes, examining the section with a low power all 

 the time. The effect of the acid is to remove the surplus carmine from the matrix and leave 

 the corpuscles deeply stained red. As soon as this is accomplished wash the section thoroughly 

 in water, and mount it in Farrant's solution. Strong glacial acetic acid accomplishes the same 

 result more rapidly. 



EXAMINATION (H).- The general characters of the section are the same as (a), only the 

 perichondrium and corpuscles are red and the matrix is colourless or only faintly stained 

 (PI. III., Fig. 2). 



B. FROM AN OLD PERSON. 



Make a number of transverse sections of the macerated tissue (p. 15). Let the sec- 

 tions include a piece which has been calcified. 



(a) Osmic Acid. Place some of the sections in a one per cent, solution of osmic acid as 

 for fcetal cartilage. 



EXAMINATION (L). Observe the perichondrium and the general arrangement of the 

 corpuscles, the corpuscles flattened at the periphery, in irregular clumps a little further in, and, 

 as one examines towards the centre, the rows of cartilage-cells produced by transverse or 

 oblique cleavage. The matrix, hyaline at the periphery, but finely granular in other parts. This 

 is best brought out by slightly shading the mirror or using a small aperture of the diaphragm. 



(H). The corpuscles The protoplasm is very apt to shrink within the capsules, and in it 

 are to be seen several black spots. These are small masses of oil which have been blackened 

 by the osmic acid, which is an excellent reagent for detecting the existence of fatty particles in 

 any tissue, and is therefore of great value. In persons above middle age, oil-drops are fre- 

 quently to be found both in the cartilage-cells of the tracheal rings and rib-cartilages. The 

 rows of cells are obvious. 



Matrix. Examine the granular part. Between the rows of cells the matrix may be found 

 to be distinctly ' fibrillated ' ; the fibres lie mostly parallel one with another. 



It is well to mount a preparation of cartilage, showing the fibrillation of the matrix in a 

 ten per cent, solution of common salt, which prevents the swelling up of the fibrils. 



($) Eosin. Place other sections in a dilute solution of eosin (p. xlv). This substance 

 stains the section very rapidly a minute usually suffices. Rinse them in a one per cent, dilution 

 of acetic acid and mount in Farrant's solution. 



EXAMINATION (L). Observe a similar arrangement of the elements. The matrix is 

 slightly red and corpuscles slightly deeper in colour. The calcareous matter deposited be- 

 tween the cells and the fibrillated parts are more deeply stained than the hyaline matrix, and 

 a kind of stereoscopic effect can be given to these calcified parts by using a small aperture of 

 the diaphragm. 



(H). Observe the highly refractive yellow oil-globules in the protoplasm of the cells, and 

 observe particularly the more deeply stained cell-capsule or ' cartilage capsule ' bounding the 

 lacuna. 



(<:) Purpurine. Place some sections in a solution of purpurine (p. xliv) for forty-eight hours. 



