

STRUCTURE OF THE ELEMENTARY TISSUES. 



39 



The cartilages of the 



ception of the epiglottis and cornicula laryngis. 

 trachea and bronchi are also hyaline. 



Mr net lire. Like other cartilages it is composed of cells imbedded in 

 a matrix. The cells, which contain a nucleus with nucleoli, are irregular 

 in sTiape, and generally grouped together 

 in patches (Fig. 39). The patches are 

 of various shapes and sizes, and placed 

 at unequal distances apart. They gen- 

 erally appear flattened near the free sur- 

 face of the mass of cartilage in which 

 they are placed, and more or less per- 

 pendicular to the surface in the more- 

 deeply seated portions. 



The matrix of hyaline cartilage has 

 a dimly granular appearance like that of 

 ground glass, and in man and the higher 

 animals has no apparent structure. In 

 some cartilages of the frog, however, 

 even when examined in the fresh state, 

 it is seen to be mapped out into polygo- 

 nal blocks or cell-territories, each con- 

 taining a cell in the centre, and representing what is generally called 

 the capsule of the cartilage cells (Fig. 40). Hyaline cartilage in man 

 has really the same structure, which can be demonstrated by the use of 

 certain reagents. If a piece of human hyaline cartilage be macerated 



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FIG. 39. Ordinary hyaline cartilage from 

 trachea of a child. The cartilage cells are 

 enclosed singly or in pairs in a capsule of 

 hyaline substance. X 150 diams. (Klein 

 and Noble Smith.) 



FIG. 40. Fresh cartilage from the Triton. (A. Rollett.) 



for a long time in dilute acid or in hot water 95 113 F. (35 to 

 45 C.), the matrix, which previously appeared quite homogeneous, is 

 found to be resolved into a number of concentric lamellae, like the coats 



