172 THOMPSON YATES AND JOHNSTON LABORATORIES REPORT 
and sometimes dense capsule, and the interior structure is of that form, in which there 
is a central or somewhat eccentric mass of aggregated granules (Plate XIII, Fig. 3). 
The protruded material is either in the form of discrete spherical granules or 
of very delicate fibrillar material, in which granules are entangled. The granules thus 
discharged may be either deeply stained blue, when methylene blue is used, or 
may be uncoloured and highly refractile. The micropyle is distinctly seen as a minute 
channel, on the one hand, continuous with the central granular interior of the cell, 
and on the other, with the exterior through a stoma on the surface. The cells exhibiting 
this process are, many of them, pear-shaped, being somewhat distorted in the direction 
in which the extrusion is taking place ; the outline of the interior and the extrusion 
may be compared to the core and the stalk of the pear. This distortion is not, how- 
ever, common to all discharging forms. The continuity of the extruded granular 
material and the granular material in the centre of the cell, through the micropylon, 
is definitely seen. 
If the same culture is examined at the end of forty-eight hours' incubation, 
it is characterized by the large number of cells which shew this process of extrusion 
(Plate XIII, Fig 4). The extruded material is, in most cases, still attached to the cell 
by its stalk, but there are also free in the culture small masses of spherical granules. 
These masses of small spherical granules have the appearance of minute cocci of vary- 
ing size, connected together by intercellular fibrillar material. I use the term coccus 
in a descriptive sense only. 
After seventy-two hours' incubation (Plate XIII, Fig. 4), there is present in the 
culture an increased amount of this small coccus-like growth ; the individual cells 
of this are spherical, and take a deep blue colouration with methylene blue. The 
large cells from which extrusion has taken place are much vacuolated and without 
granules. The free granules occur singly, in pairs, and in groups, and shew a larger 
average size than those in the earlier cultures. 
I have examined many of these glucose broth cultures after more prolonged 
incubation, but, except in two instances, have been unable to determine any further 
development of this growth of small spherical granules. When such cultures are 
plated on glucose agar colonies of A develop after three or more days, according to 
the age of the culture, but, with the exception of the two occasions which 1 have 
just mentioned, no colonies of any other type. On these two occasions there 
multiplied in the glucose broth cultures of A an organism of a type much smaller 
than the A specimens, spherical and oval in shape, and from 5// to 3// in 
diameter ; these organisms were abundant in the cultures, and when plated on glucose 
agar developed as separate colonies after twenty-four hours' incubation at 37° C. 
Example 1. Glucose broth culture inoculated May 16 ; plated June 1 on 
glucose agar ; colonies of the small type alone developed ; microscopically in the 
glucose broth both the small type and the A type were seen, the former abundant. 
