G. S. Graham-Smith 
27 
more accurately described as lateral outgrowths composed of spirally 
twisted threads, are thrust out into the medium. At other places the 
attempt at loop formation results in the chain becoming much twisted 
on itself, and gives rise to the appearance of knots on the chain. 
Finally the colony consists either of a single knot or a series of knot¬ 
like masses, surrounded by wavy outgrowths composed of spirally twisted 
chains of bacilli. 
Parallelism such as is seen in superficial colonies never occurs in deep 
colonies. In Plate IV (Figs. 1 to 10) a series of photographs (x about 
80) are reproduced illustrating the formation of a deep colony from a 
single anthrax bacillus. In Fig. 1 a long wavy chain is seen, whose 
development from a single bacillus has been followed. Fig. 2 
(15 minutes) shows an increase in length and a marked irregularity in 
the chain some little distance to the left of the centre. In Fig. 3 
(45 minutes) the irregular area previously seen has become more 
distinct. In Fig. 4 (80 minutes) two small processes, just beginning 
to develop, can be made out one on each side of the irregular area and 
some distance from it. This figure also shows projecting processes one 
on each side of the irregular area. In Figs. 5 and 6 (117 and 135 
minutes) the development of these processes may be followed. In 
Fig. 6 the irregular area now resembles a knot. Figs. 7, 8 and 9 
(165, 210 and 285 minutes) illustrate further development. Fig. 10 
(450 minutes) shows the fully developed colony. The irregular area 
first noticed has developed into a large knot, and several smaller knotted 
masses, produced in the same way, are seen along the length of the 
colony. Many irregular processes project laterally from the colony, 
some of which have developed knots in their length. At each end the 
colony terminates in a wavy thread. 
In Figs. 6 to 10 another colony can be followed developing above 
the original colony, and in Figs. 7 to 10 a third colony developing 
below it. 
Owing to their uneven disposition photographs of deep colonies 
have to be taken at such a low magnification that the details of the 
development of knots cannot be followed. While the photographs 
just described were being taken drawings were made at the same time 
on a larger scale. Diagram 2 reproduces a series of drawings showing 
the development of the irregular area from the condition seen in Plate IV, 
Fig. 2 to the condition seen in Plate IV, Fig. 5. 
In Diagram 2, Fig. 1 (15 minutes) the structure of the irregular 
area is clearly shown. It is caused by several definite loops in the 
course of the chain, at two of which (A and B) the chain is sharply 
