ORGANIZATION OF THE BACTERIA. 4] 
EXTRACT FROM PAPER “ON THE EXISTENCE OF 
FLAGELLA IN BACTERIUM TERMO,’”’ BY W. H. 
DALLINGER, F.R.M.S., AND J. J. DRYSDALE, M.D., 
F.R.M.S. 
“Tn the summer of 1872, some very fine specimens of S. volutans came 
under our notice, and were carefully examined. We were enabled fully 
to confirm Cohn’s discovery, and demonstrated repeatedly the presence 
of a pair of swiftly lashing flagella. The drawing at 6, Fig. 1, was made 
from a specimen magnified 1,500 diameters (diminished by $). 
“ Having closed for the present our Monad researches, we have been 
stimulated by the hope that the experience gained by these might enable 
us to prosecute similar investigations into the true life history of bac- 
teria. We have commenced the work this summer, and, guided by the 
analogy of S. volutans, we have been led to make several continuous 
efforts to find whether or not there existed a flagellum or flagella in 
B. termo. The task, of course, under the best circumstances, must be a 
a difficult one, from the extreme minuteness of the object. We tried 
each of Powell and Lealand’s powers successively, from the 34; to the 345, 
but with no definite result. Repeatedly we both saw vortical action at 
both the distal and proximal end of the termo, but could not absolutely 
see the organ causing it. But in the process of our investigations we 
made very close and careful observations on the fission of this form: we 
do not purpose now to describe the process, but merely to point out a 
phenomenon that further confirmed our suspicion of the presence of an 
invisible filament. In separating into two, the jointed rod of sarcode 
which is in process of division shakes to and fro at the constriction, as if 
the constricted part were a hinge; and at length a clear separation takes 
place to quite the length of the original termo (sometimes longer), and 
there is no visible connection between them; nevertheless they act as one crea- 
ture, so that if one moves in any direction, the other goes with it, just as the two 
parts did before separation; showing that, although we cannot see the con- 
nection, there must be one; and the presumption was that it was a fine 
filament, such as we detected in the fission of some mcnads.! We could 
make no further progress in the question apparently ; but our attention 
was called to the new {th objective prepared by Messrs. Powell and 
Lealand, with which we were soon supplied. We used it at first with 
the ‘supplementary stage’ for very oblique illumination, supplied by 
the same makers, and this has the advantage of throwing the light in 
only from one direction. We were soon convinced of the exquisite per- 
formance of the glass when used as an immersion. Amphipleura pellucida 
was not merely seen to be striated clearly and sharply, but the striz 
“M. M. J., vol. x., p. 55; and vol. xi., p. 8.”” 
