Gr. S. Graham-Smitii 
29 
outgrowths, in most of which knots have been formed at various places, 
and all of which possess secondary lateral processes. 
Plate IV, Fig. 12 illustrates some young deep anthrax colonies. These 
consist of central knots and numerous wavy radiating processes. This 
preparation was made with very dilute agar which limits the growth 
to a much smaller degree than does ordinary agar. 
Plate IV, Fig. 13 shows deep and superficial growth in the same 
colony. The colony first developed just below the surface of the agar 
and grew in the typical manner. This portion is seen in the lower left 
hand part of the photograph. Later a portion of the colony reached 
the surface and produced on it a typical superficial wavy growth seen 
in the upper and right hand portions of the photograph. 
In fluid media long chains occur, but owing to their growth being 
unrestricted they produce neither loops nor tangles. 
The conditions seen in stained preparations and in “ contact ” 
preparations and the observations on living specimens just described 
all tend to show that in the “ loop forming ” group, as illustrated by 
B. anthracis, although the protoplasm becomes segmented and numerous 
bacilli are produced, the membrane or capsule surrounding the chain 
apparently remains continuous, and keeps the newly formed bacilli 
closely connected with one another. This capsule is seldom completely 
ruptured, and each colony therefore consists of a single uninterrupted 
chain of bacilli. Under the conditions of observation, or on surface 
cultures, the bacilli are only free to grow horizontally. As growth is 
taking place, not only at the ends, but in all parts of the chain at the 
same time, curves ultimately developing into loops are formed in order 
to accommodate the rapidly increasing length of the chain. 
If the centre of a piece of string is placed between two parallel 
glass plates, separated from each other by a distance equal to the 
diameter of the string, and the string is gradually pushed between the 
plates from fixed points on each side, the changes which occur in a 
young colony of a loop forming bacillus are to some extent reproduced. 
In the depth loop formation is hindered by the consistency of the 
medium and consequently the chain as it grows tends to develop tangles, 
which subsequently become knots, and twisted lateral outgrowths. 
Group II. The “folding” group. 
During the first stages of growth on the surface the original bacillus 
grows in length and divides into two rods of equal length, separated 
from each other by a very distinct interval. By further growth a straight 
