434 E. T. Bell. 



SUMMARY OF PART II. 



A peculiar open-meshed tissue (preadipose) precedes the formation 

 of true adipose tissue. The renal preadipose tissue is formed into 

 well-defined lobules a long time before the true fat cells appear. The 

 masses of preadipose tissue in the omentum are much less sharply 

 marked off than those of the kidney and persist only a short time 

 before the formation of the fat cells begins. The subcu'taneous 

 preadipose tissue is found as masses around llie blood vessels (Text 

 Fig. 1) and persists only a short time in the preadipose condition. 



The preadipose tissue consists of loosely-arranged cells with two 

 or more long coarse processes. A great many fine connective tissue 

 fibers occupy the ground substance of the tissue (Fig. 8, Plate I; 

 Fig. 0, Plate II). The branched cells may contain fat droplets 

 a long time before they begin to assume the rounded form. 



The preadipose tissue is clearly a fibrillar connective tissue. My 

 results support Flemming's view that adipose tissue is a modified 

 fibrillar connective tissue. 



In the formation of a fat lobule the cells adjacent to the blood 

 vessel are filled with fat first. The filling of the cells with fat ex- 

 tends from the blood vessel outwards in all directions. This process 

 is closely similar to the deposition of fat in the liver where it is 

 deposited first in the cells immediately adjacent to a vein and later 

 into those lying farther out. 



The branched preadipose cell becomes rounded by the accumula- 

 tion of fat in its interior. Its processes are absorbed. 



The cell membrane is differentiated from the peripheral proto- 

 plasmic layer of the cell. It begins to form when the cell is yet 

 branched. 



The Altmann granules are found in the protoplasm of all fat cells. 

 They are first observed when the cell is yet branched and before the 

 first fat droplets are formed. 



The mass of adipose tissue increases in amount in fattening (a) 

 by the increase in the size of its cells, (b) by the formation and filling 

 of new cells in the interior of the lobule, (e) by the formation of new 

 lobules. 



