474 HOPE HIBBARD 



This emulsified condition is a characteristic of fats. It seems 

 probable that the original large drop of fat is being split up 

 into smaller parts and that the scattered fine partir'les of 

 blackened material throughout the cell have been formed by such 

 emulsification of larger masses. 



Sudan III, a specific stain for fat, was used on this material, 

 but gave no decisive results because the drops had been previously 

 blackened and naturally could not be stained red. A further 

 proof of their fatty character was obtained by soaking the sec- 

 tions for twenty-four hours in oil of turpentine. After this treat- 

 ment the black droplets were completely dissolved out. Since 

 turpentine is a fat solvent, the material which was removed was 

 probably fat. 



The large groups of fat droplets are slightly more numerous in 

 the region of the nucleus than they are in the more distant parts 

 of the cytoplasm. This is of interest in the hght of the views of 

 Schreiner, PopofT, and others, that granules of nuclear origin 

 pass through the membrane and give rise to fat droplets. The 

 granules are beheved to come from the nucleolus. 1 he evidence 

 given here of the accumulation of fat near the nurleus shows noth- 

 ing more than the fact that they are associated with some kind 

 of nuclear activity. It is also true that an occasional oocyte 

 has been found on the slides in which there is always a large nu- 

 cleolus present which is entirely absent in the ripe egg. 



The continued splitting of the large drops into minute droplets 

 and the dispersal of the latter through the cytoplasm is illustrated 

 in figures 2 and 3. These show eggs from the same series from 

 which figure 1 was drawn, in stages twenty-five minutes and one 

 hour and forty minutes, respectively, after* insrniination. As 

 development proceeds, there is a gradual decrease in the amount 

 of blackened material present. As the cell prepares for the first 

 division the fat droplets are vau^h fewer, and in the two-celled 

 stage none are visible. It is highly probable that these cells do 

 not show as much fat as is present in the living egg, because some 

 of it must have been dissolved out in the processes of preparation, 

 but the fact that a definite series of changes can be demonstrated 

 is a true indication of what actually occurs. 



