586 C. CLIFFORD DOBELL. 
Tue Mernop oF Sprores-ForMATION IN B. BUTSCHLII, 
B. FLEXILIS, AND OTHER Disportc BacTERiA,. 
In order that I may be able to discuss the general bearing 
of the foregoing observations on the central problem involved, 
I will here briefly summarise the descriptions which have 
been given of spore-formation in other disporic Bacteria. 
First, I will recapitulate the process—the so-called “sexual” 
process—of spore-formation in B. biitschlii (Schaudinn, 
1902) and B. flexilis (Dobell, 1908). The process is essen- 
tially the same in both (see text-fig. B, A, p. 589). A large 
individual (A 1), containing numerous chromatin granules, 
almost divides itself into two equal daughter-cells (A 2). The 
division is not completed, and subsequently all trace of it 
disappears (A 3). ‘he granules now arrange themselves in 
the form of an irregular spiral, and at the same time begin 
to travel to opposite poles and mass themselves together to 
form the spore-rudiments (A 3, 4). Round these is formed a 
spore membrane, which gradually hardens and so gives rise 
to the completed resistant spore (A 5, 6). The remains of 
the cell, including a part of the chromatin spiral, perish. 
Such is the process in these two Bacteria. It we search 
the literature bearing on the matter, we find that disporic 
forms are remarkably few—in many cases the existence of 
such forms is even denied, and it is stated that all Bacteria 
are monosporic. Several disporic Bactéria have, however, 
been observed ; though in many cases it seems probable that 
the disporic individuals were exceptions, and monosporic 
individuals the rule. Prazmowski (1880) figured a large 
individual of a Clostridium sp. which possessed two ter- 
minal spores. Normally, however, but one spore is formed. 
In 1881 Kern described a large Bacillus from kephir, and 
proposed to name it Dispora caucasica, n. g., n. Sp., on 
account of the fact that it regularly formed two terminal 
spores in each cell. De Bary (1884) in his text-book states 
that a single bacterial cell produces but a single spore :— 
