SUPRARENAL GLAND—EFFECTS OF INANITION 225 
it is desired merely to determine the relative proportions of 
parenchyma versus stroma, it is necessary merely to compare the 
weights of the paper representing the corresponding areas. In 
this way the results summarized in table 3 were obtained. These 
results are of course merely approximate, based upon the as- 
sumption that the areas selected represent the typical or average 
condition for the entire gland. 
For the volumetric determinations on parenchyma cells and 
nuclei (table 4) a similar plan was used. In this case a Zeiss 2- 
mm. apochromatic objective with ocular no. 4 was used, giving 
at table level a magnification of about 1600 diameters. Typical 
fields were selected and drawn with the camera lucida, outlining 
parenchyma cells and nuclei (stroma and vessels omitted) in the 
various zones of the cortex and medulla. No change of focus is 
permissible while the drawing is being made, since the volumetric 
calculations are based upon the assumption that it represents a 
true optical plane. ; 
The further procedure is as follows: The paper representing 
the areas drawn from the various zones is weighed (to the milli- 
gram). Then the nuclei are cut out with a sharp-pointed scalpel, 
the paper resting upon a wax plate. The paper representing the 
nuclear areas and the remainder (cytoplasm) are then weighed 
separately. From the weight of the nuclear areas, the magnified 
area in square centimeters is calculated. This divided by the 
square of the magnification and by the number of nuclei involved 
gives the average actual area per nucleus. If we assume that the 
nuclei are spherical and not greatly different in size, the average 
area per nucleus in a given optical plane should, according to the 
rules of solid geometry, represent two-thirds the area of the cor- 
responding great circle. 
This result is derived as follows: The volume of any sphere 
equals two-thirds the volume of the circumscribed cylinder. The 
diameter of the sphere equals the height of this circumscribed 
cylinder, and the area of the great circle of the sphere equals the 
cross-sectional area of the cylinder. The volume of the cylinder 
is obtained by the product of its cross-sectional area x height of 
cylinder. The volume of the sphere may be obtained by the 
