ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
693 
paper. The funnel-filter (fig. 114) is an ordinary copper funnel along the 
edge of which a flat ring of tinned iron A is fastened. This is in two 
parts, the outer being fixed, while the inner one is movable and serves 
for the support of a circular metal net D, which closes the opening of the 
funnel. Upon this lies another flat ring B, and the two are fastened 
Fig. 114. 
together by four clamps E, and in order to hermetically close the space 
a rubber band C is interposed. F is a projection or handle for fastening 
the apparatus to a support. 
The bougie-filter (fig. 115) is somewhat like the porcelain bougie- 
filter in appearance, though shorter and wider. It is made of metal net- 
Fig. 116. Fig. 117. 
work. The top and bottom as well as a strip 2 cm. broad at each end are 
made of metal plate and are exactly alike. In order to work these filters 
the ordinary aspiration apparatus is used. The tube of the funnel is 
placed in a Kitasato’s bottle, and the bougie-filter is connected with a 
similar receiver by a rubber ^tube fastened on the nozzle B. A thin 
emulsion is obtained by placing the pounded up material on the metal 
