422 E. T. Bell. 



Small fat droplets were also noted in the subcutaneous preadipose 

 tissue of the inguinal region and of the brisket. But the preadipose 

 tissue of these regions persists only a short time before the cells 

 are filled with fat, so this condition is hardly comparable to that 

 in the renal preadipose where the branched cells contain fat droplets 

 a long time. 



Preadipose tissue of the omentum. 



The time of the first appearance of this tissue varies considerably. 

 The youngest foetus in which it was noted was 33 cm. long. This 

 specimen showed a very early stage. The preadipose tissue can be 

 distinguished from the adjacent mesenchyme only by its being a 

 sheet of tissue in which the nuclei are decidedly closer together than 

 elsewhere. The cells are similar to those of the preadipose. The 

 mass of tissue is not at all sharply marked oif from the adjacent 

 mesenchyme, and it does not show a marked reticular structure. 



Text Fig. 5 shows a later stage — a section through the preadipose 

 tissue of a 40 cm. foetus. The tissue here forms a well-defined 

 flattened mass. Its finer structure is shown in Fig. 9, Plate II. It 

 will be noted that it is not essentially different from renal preadipose 

 tissue. The cells are of the same type. The fine collagenous fibers 

 stain a little stronger and are somewhat coarser than those of the 

 renal tissue. Large collagenous fibers (cf) occur in the omental 

 tissue. This tissue does not have a pronounced reticular structure 

 such as seen in the renal region. 



In many places in the omentum the preadipose is not nearly so 

 compact as that shown in the figures. The same sheet of tissue 

 shown in the figure has a very diffuse arrangement in another part 

 of the same section. The finer structure of the tissue remains the 

 same, but the nuclei become bunched in small groups (5 or 6 to 

 a group) separated by intervening mesenchyme. This diffuse 

 arrangement does not seem to correspond to the blood vessels. iN'o 

 true fat cells are yet formed in this specimen. 



The omental preadipose tissue is by no means so sharply defined 

 as the renal even in its most compact places ; but it is a mass of tissue 

 formed some time in advance of the development of true adipose 



