THE MICROSCOPE. 13 
The intercellular substance of hyaline cartilage is apparently 
structureless, but it is really traversed by numerous delicate fibrils 
which can be demonstrated by macerating the sections in a 10 per 
cent. solution of sodium chloride, which dissolves out the cement 
substance, and then staining in picro-carmine. 
Lymph Channels.—The lacunz communicate with each other 
through numerous channels, presumably belonging to the lymphatic 
system. They can be demonstrated by soaking thin sections in 
ether for an hour and then placing them, while still moist, on a slide 
and covering them with collodium. Examine with a high power. 
Hyaline cartilage is found in the articular and costal cartilages, 
the thyroid and cricoid cartilages of the larynx, the rings of the 
trachea, and the cartilages of the bronchi, and the septum and cartil- 
ages of the nose. MHyaline cartilage is the cartilage from which the 
bones are formed. 
Frsrous Cartiiace.—Make thin sections from an intervertebral 
disc, stain, in picro-carmine, dehydrate and mount in balsam. 
Examine first with a low and then with a high power. The outer 
‘portion of the section is of hyaline cartilage. The fibrous cart- 
ilage is distinguished by the bands of white fibrous tissue which 
traverse the intercellular substance. Treating a section with dilute 
acetic acid will cause all the fibers to swell, showing that they are of 
the white fibrous and not elastic variety. The cells usually arranged 
in rows, resemble those found in hyaline cartilage, although they are 
not so numerous and are more compressed and flattened. Fibro- 
cartilage is found in the intervertebral cartilagze and generally, 
though not always, composes the interarticular and sesamind eartil- 
ages, the cartilage of the symphisis pubis and margin of the glenoid 
fossa. Hyaline and fibrous cartilage are intimately related, the 
former often changing partially or completely into the latter. 
Euastic Cartrinace.-Make sections from the external ear or 
epiglottis, stain with hzematoxylin, dehydrate and mount in balsam. 
The elastic fibers found in the intercellular spaces are branched and 
unite to form a close network. The cells are round and inclosed in 
large lacunz, and are scattered irregularly through the tissue. 
Elastic cartilage is found only in the cartilage of the external ear, of 
the eustachian tube, of the epiglottis, and the cartilages of Wrisberg 
and Santorini in the larynx. 
Cuances in Cartinace.—As the individual matures, cartilage 
undergoes various changes, which are especially marked in old 
age. These changes are most marked in hyaline cartilage. Make 
