1887.] MICROSCOPICAL JOURNAL. 123 
very different kind is the rule. In sections cut in most parts of the gland 
there are to be seen three kinds of epithelium cells; these three are repre- 
sented in figures 2, 3, and 4. Some are very low, and their side walls can 
not be seen, but their position may be located roughly by the distances apart of 
the nuclei—a method of determining the shapes of cells which is lacking in 
exactness, but may be used if used rationally. These cells, we infer from 
what we can see in their section, are low and broad, very unlike those 
described and figured in figure 2. They are to be seen at D in fig. r and in 
other places, and cells very like them are to be seen lining the sack—figure 
1, &p. At Yu the transition from one to the other kind may be seen where 
the sack enters the substance of the gland. 
A third form of cell, of different outline from those mentioned, is also 
detected in linings of other cavities of the gland. These are shown in fig- 
ure 3. They are taller than broad, and hence in sections vertical to the base- 
membrane they appear to be columnar in outline instead of squarish or broad 
and flat. We have thus determined that there are three forms in which the 
cells lining the cavities of the gland may appear. 
6. Size of the cell.—In addition to determining the shape of the cell, 
one should determine its dimensions. This may be done in a variety of ways. 
One way, which is convenient and accurate, is the following; after it is 
learned others may be followed if any one desires. The way which is, ‘per- 
haps, most desirable is the one followed in making plate iv. The drawing, 
let us say, of figure 2, was first sketched in outline with a camera lucida. In 
making this dtawing with the camera such details received most careful 
attention as the outer wall and basement membrane, shape and position of 
nuclei, and distance of nuclei from each other, and indications anywhere of 
side walls, while the protoplasmic content was drawn in free hand. As soon 
as the sketch of the section was completed the instrument was kept in its 
position and a stage micrometer substituted for the slide and its lines drawn 
on the paper. These, of course, had the same enlargement as the section 
before it, and its actual size is known. It may, therefore, be directly com- 
pared with the drawing of the cell. Thus in fig. 2 the scale a Opa the 
drawing Bs the cells on the left, and the cells ens directly measured, sary in. 
-4 
high by Too in. across, ina few cases, to Tio0 in. high by 33407 im. across, 
in other instances, and an average of ;,5,5 in- X zag in- 
By consulting the other figures the reader will. find accompanying them 
the scale. Since these scales are of unequal length in the figures, the infer- 
ence is that the various sections are not equally magnified, which is true, 
the three figures having been drawn at different times and without any at- 
tempt at equal enlargement. We learn, by applying them to the measure- 
ment i the cells, that the columnar cells are, some of them, ;};35 inch high 
py sano inch broad; the flat cells are ;;2,, inch high and presumably about 
a¢o0 broad. It is a very good plan to always draw the scale with every 
drawing of the object. Very many good histologists have very inexact ideas 
of the size in connection with the cells they study. 
c. Contents of the cells.—Within the boundary of all the cells of the 
alveolus one will see colored matter, which is not homogeneous and _ trans- 
parent but very finely granular. This is called the ‘cell contents,’ or 
‘cell substance.’ It is in the cells under consideration composed entirely of 
‘protoplasm.’ It requires training and the study of many different kinds of 
cells to be able to recognize protoplasm by its appearance, after staining, 
and this matter will come up again as we examine other cells, some of which 
will be found to contain non-protoplasmic material. But, in the cells of the 
healthy green gland, protoplasm only is to be detected after such treatment 
as has been described. 
