CHAPTER 19 



Factors affecting stratification and breaking 



a. Centrifugal Force. Plate XIII 



With low forces, it takes longer to break the eggs apart, and the eggs 

 have become well stratified before breaking. The white half is much 

 larger than the red half. 



With high forces obtained by the air turbine, the egg breaks quickly 

 before it has become well stratified. The white half is much smaller 

 than the red half The red half can be restratified like the whole egg if 

 recentrifuged (Plate XIII, Photograph 12). 



With intermediate forces, the time for breaking and the stratification 

 is intermediate, and the white half and red half are more nearly equal 

 in size. These results are given in Table 10 and in Photographs on 

 Plate XIII (see E. B. Harvey, 1941a). 



b. Hypo- and Hypertonic Sea Water. Plate XIV 



When eggs are kept and centrifuged in hypotonic sea water (60%, 

 80%), it takes longer to break them apart. The granules are well 

 packed so that few remain in the white half, which is much larger than 

 the red half. It is also much larger than the control (100% sea water), 

 while the red half remains about the same size. 



When eggs are kept and centrifuged in hypertonic sea water (125%), 

 the clear area is small, the mitochondrial layer very thick, being spread 

 over a smaller area and in many cases well marked. The pigment is 

 not well separated from the yolk, there being no clear line of demar- 

 cation. It is inaccurate to speak of "well-stratified" eggs, since they 

 may be well stratified with regard to one layer (mitochondria) and 

 poorly stratified with regard to others (yolk and pigment). The white 

 halves are much smaller than the controls, the red halves about the 

 same size. The eggs break more readily in hypertonic than in normal 

 sea water. These results are shown in Table 1 1 and on Plate XIV (see 

 E. B. Harvey, 1943). 



