ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 229 
elongation of the nozzle in the form of a fine pipette marked with 100 
divisions. This shape is intended for the injection of quantities which 
may be as minute as 0-01 ccm. 
Z is a mark indicating the place to which the piston should he with- 
drawn before introducing the injecting fluid. 
Improved Filter for Microscopical Fig. G2. 
Water Analysis.* — Mr. D. D. Jackson 
lias devised an attachment to the Sedg- 
wick-Kafter filter which obviates the chief 
defect of the original apparatus. By the 
older process many Protozoa escaped 
enumeration, and this difficulty has been 
got over by means of the attachment to 
the filter-funnel, which holds back a de- 
finite quantity of the original water in the 
funnel. This attachment consists of a 
prolongation of the filter-tube, and is 
closed at the bottom by means of a solid 
rubber stopper. A smaller tube is con- 
nected with the main tube by a T-joint, 
and rises just to the level of the 6 ccm. 
mark on the funnel. This tube is of such a 
height that when the solid rubber stopper 
is in place, all the water may filter through 
the sand, except five cubic centimetres. 
Automatic Measuring Pipette. f — 
Herr F. Kern describes an automatic pi- 
pette for measuring off definite quantities 
of germ-free fluids. Its chief advantage 
is that it can be worked by one person. 
It consists of three parts (fig. 62) : — a T- 
shaped glass tube with a three-way tap at 
A, a reservoir, and a float- valve c. The 
reservoir may be made in one piece with 
the three-way tap, or connected at B by a 
rubber tube. The float c has its upper 
end rounded off to fit into the narrowed 
part of the reservoir, and so close the 
upper aperture. The reservoir is filled 
from below by siphon action ; and as the 
fluid rises, the float is pushed up so that 
it closes the reservoir when the latter is 
full. The horizontal tube is connected with the long arm of the siphon, 
and the vessel containing the fluid with the short arm. The action is 
started by sucking at the upper end of the pipette. When the reservoir 
is full, the tap is turned to the left so that the fluid is evacuated below. 
This done, the tap is returned, after which the apparatus fills itself. 
For different quantities of fluid, reservoirs of different sizes are required. 
An apparatus similar in principle was described by Kuprianow.J 
* Technology Quarterly, xi. (1898) pp. 241-5 (1 pi.). 
f Centralbl. Bakt, u. Par., l te Abt., xxv. (1899) pp. 75-7 (1 fig.). 
X Cf. this Journal, 1894, p. 400. 
