E. O. LONGLEY
191
experienced. The technique described by Turner of placing the slide between
several layers of blotting paper, and exerting firm pressure on the coverslip
with a roller to the extent of Newtonian ring formation, constantly resulted
in either stationary fields devoid of all but the coccoid forms, or slightly
thicker fields including the variants, but with these retaining some degree of
Brownian movement. This, though so slight as to be barely perceptible to
the eye, quite precludes effective photography. It was ultimately found
that if the drop of effusion was so small that with very firm pressure as des-
cribed the film of fluid did not extend to the edge of the coverslip, the escape
of the bodies on to the blotting paper was prevented, and perfectly rigid
preparations rich in the specific bodies could be prepared.
Zeiss optical equipment has been used throughout.* The camera was
the Zeiss Miflex, used with the Kodak Panatomic-X roll film (4.0×6.5 cm.).
The source of light has been the Zeiss 100-watt Pointolite lamp, used with
the Cardioid condensor. Exposures have varied from 2-15 minutes, but with
the Contax, 5 minutes has usually proved the most satisfactory.
Unfortunately, no apochromatic objective was available, and it was
necessary to make the most of the Zeiss achromatic dark-ground objective,
N. A. 1.25 (0.85), with the × 5 or × 7 ocular, giving magnifications of ×450
or × 630. The subsequent enlargement of films up to × 3 has given magni-
fications up to × 1890. This is demanding rather too much of the lens em-
ployed, and such enlargement is more or less ' empty '. Variants observed
in preparations unsuitable for photography by reason of Brownian movement
have been recorded by drawing.
(4) The dark ground examination of the normal pleuritic and pericardial
effusion in goats reveals coccoid bodies, varying in size, and numerous short,
straight, and very delicate filaments, of different lengths but of uniform
thickness, presumably fibres of fibrin. The numbers of these present in any
preparation depends on its thickness, but is never great.
In pneumonic material, innumerable coccoid bodies are present, all in
active Brownian movement, and many indisputably motile. These vary
in size from the limit of visibility to that of a small staphylococcus, but
average about 0.3—0.5 µ. In all the accompanying dark-ground photo-
micrographs such bodies are represented. Probably the next most common
form is stellate, with from three to six arms (Diagram 1 and Plate XII, figs.
1 to 4). Variants with marked elongation of one or more arms as shown
are common, (Plate XII, fig. 5 and Plate XIV, Diagram 1). A third, and fre-
quently observed form is a short filament with closely attached coccoid bodies
(Plate XII, figs. 4, 6 and 7 and Plate XIV, Diagram 3).
Another form, corresponding closely with that designated by Turner
' genethode II' is shown in Plate XII, figs. 8 and 9, and Plate XIV, diagram
2 and consists of a spherule, with a clear centre, from which radiate one or
more short fingers, and which has often attached granules, probably the
progenitors of the filaments (Plate XIV, Diagram 2). Plate XIV, Diagram 3
represents a phase, described by both Turner and Tang with the bovine
organisms, but which we have unfortunately failed to photograph. It consists
* For the loan of this apparatus the author is indebted to Dr Pandit, Director of the
King Institute, Guindy.