CONNECTIVE TISSUES CARTILAGE. 



67 



disposing to the accumulation of fat. It is probable that every form of cell 

 may become infiltrated with fat, as a stage or form of degeneration. Fat 

 fulfils the following important objects in the animal economy : It diffuses 

 pressure, and is, therefore, largely developed on the palms of the hands, soles 

 of the feet, buttocks, and female breast. By its disposition beneath the skin 

 generally, it forms a warm investment for the body that materially dimin- 

 ishes the loss of heat by radiation and conduction; at the same time it gives 

 a smooth, flowing, and agreeable contour to the surface which otherwise, 

 especially near the joints, would present hard and angular outlines. It forms 

 au elastic pad, or cushion, in the orbit, on which the eye can rotate ; and in 

 the heart, by filling up the interstices of the vessels and the irregularities of 

 its surface, it fulfils a similar function, enabling this organ to perform its 

 ceaseless movements with the least possible amount of friction. It confers 

 lightness, and probably a certain degree of elasticity, on the bones as well, 

 indeed, as on all other tissues into the composition of which it enters. It 

 constitutes a storehouse or reserve fund of hydrocarbouaceous material, 

 which, when required by the economy, can readily be absorbed into the 

 blood ; the process of absorption being facilitated, as Matteucci has shown, 

 by the alkalinity of the fluid that moistens the outer surface of the cells. 

 Lastly, if we may judge from its constant presence when these are taking 

 place, it plays an important part in the processes of growth and develop- 

 ment. 



According to M. F. Czajewicz, 1 the cells of adipose tissue originate in the 

 corpuscles of ordinary connective tissue. These, in any part that is about 

 to become the seat of deposit of fat, increase in size, assume a spherical form, 

 and become filled with a mist of small fat-drops (a, Fig. 27). At a stage 

 slightly more advanced (b), the mist becomes condensed into small drops, 



FIG. 27. 



FIG. 28. 



Successive stages in the Development of Fat. Example of Endogenous Cell-formation. 



which gradually acquire a larger size and greater distinctness (c), and ulti- 

 mately blend into one large oil-globule (d). Toldt, however, maintains that 

 fat-cells in the earliest stages of their development have no cell-wall, and 

 constitute a tissue quite sm ^enen's and distinct from connective tissue. In 



Keichert's Archiv, 1866, Heft iii, p. 289. 



