SYMPATHETIC CELLS: ALBINO RAT 283 
Serial sections of the entire ganglion were cut 8 u in thickness. 
Heat from an electric bulb was used in flattening the sections. 
The slide was placed underneath the bulb, so that the water that 
served to float the sections on the slide, also chilled them from 
beneath, when they were spread by the heat. 
The procedure in staining was as follows: The sections were 
passed from xylol down through the graded alcohols to water, 
and then put for five minutes in a saturated solution of lithium 
carbonate, after which they were stained for two or three minutes 
in a one-third saturated solution of thionin. They were then 
passed up through the graded alcohols to xylol and mounted in 
acid-free balsam. So far as possible, the plane of section was 
made perpendicular to the short axis of the ganglion, thus giving 
the maximum area. 
MEASUREMENTS OF THE CELLS AND NUCLEI 
The cells and nuclei of the ganglion were measured with an 
eyepiece micrometer, using a Zeiss ocular no. 6, and objective, 
4mm. Each division in the micrometer scale was equivalent 
to 4.47 u. The measurements were made in the following way: 
In the case of each specimen a section at the middle of the series 
was selected. Starting both ways from this, four more sections 
were selected, two in each direction, by skipping every other 
section. In this manner five sections altogether were chosen 
and marked for study. In each of the five sections the two 
largest cells were measured; thus ten cells in all were measured 
in each ganglion. 
There were four principal points kept in mind when selecting 
the cells for study: First, the cells must be the largest in the 
section; second, they must be uninuclear; third, the nucleus 
must be located at or near the center of the cell and must be 
fairly large; fourth, in the nucleus at least one nucleolus must be 
present. 
Under these conditions, the measurements made on the cells 
and nuclei are considered to represent the maximal longitudinal 
and transverse diameters of each cell and nucleus taken close 
to their median planes. It was often found in this study that 
