CARTILAGES. 291 



cells of some of the species of which it would be impossible 

 to distinguish from the isolated cartilage corpuscles of the 

 epiglottis and intervertebral cartilages, 



In these methods of multiplication, cartilage cells would 

 appear almost to stand alone in the animal economy : thus it 

 is certain that the red blood corpuscles, epithelial cells, and 

 their various modifications into epidermis, nails, pigment 

 cells, and hairs, are not multiplied either by division or by 

 the development of secondary enclosed in primary or parent 

 cells. 



The analogy existing between the cells of cartilages and 

 those of certain algse has been noticed by Dr. Carpenter in 

 the 3d edition of his " Principles of Human Physiology." 



The Intercellular Substance. Very young cartilages, and 

 also the smaller ones of adults are constituted almost entirely 

 of cells, with but little admixture of intercellular substance. 

 As, however, these young cartilages grow in size, the relative 

 amount of this substance increases, and the space between 

 the cells becomes greater. 



The augmentation of the intercellular substance takes 

 place principally by a deposit of new layers on the exterior 

 surface during j;he period of the development of cartilages ; 

 this mode of increase is proved by their separation after long 

 continued maceration into distinct laminae. 



A second mode of increase of the intercellular substance 

 has been stated to exist by Henle *, principally in the car- 

 tilages of ossification, and under no circumstances in the 

 fibro-cartilages, viz., by the thickening of the walls of the 

 cells which become confounded with or melted down into 

 the intercellular substance, the cavity in which the cells are 

 lodged being diminished, or this also augmenting at the same 

 time. The proofs adduced in favour of this method of in- 

 crease are not convincing. 



Jt has already been stated that in the true cartilages which 

 are subject to ossification fibres appear; these fibres as well 

 as the analogous ones of fibro-cartilages, are probably of a 



* An.it. Gen., vol. vii. p. 376. 



