4 RAYMOND PEARL AND ALICE M. BORING 



up an acid stain. They remain strikingly clear, when the con- 

 nective tissue all around them is highly colored. So great is the 

 contrast that they show distinctly even at low magnification 

 in a section such as figure 1. Furthermore, they are found in 



Fig. A Part of follicle of wall of medium sized oocyte in hen ovary. (X i)50.) 

 Compare figure 2. 



Fig. B Part of thoca interna of sixth discharged follicle in hen ovary, show- 

 ing many vacuolated lutear cells. (X 9.50.) Compare figure 0. 



