1895 



THE MICROSCOPE. 



181 



riage, as ia cutting celloidin. With fresh pith somewhat 

 thinner sections may be cut. Upon examination the slices 

 will be found to be perforated at regular intervals by open- 

 ings caused by cutting through the very thin cellulose 

 walls of certain of the pith cells. A good supply of these 

 little filters can be cut and kept ready for use at any time. 

 The next step is to cut some ordinary white filter paper 

 into disks or squares one inch in diameter. With a damp 

 tooth-pick moisten a point, about the size of one of the 

 elder filters in the center of one of these disks. By 

 means of a heated wire, saturate all except the central 



moistened portion of this disk with parafiine. Prepare a 

 discoidal pad, composed or ten or twenty superposed 

 thicknesses of filter paper and upon these place the disk 

 saturated with the paraffine. An ordinary, extra large 

 live-box, provided with a mica cover, in the center of 

 which a perforation 5-8 inch in diameter has been made, 

 is a good device for holding the disks together. The ac- 

 companying figure shows the apparatus in vertical section. 

 The mode of operation is as follows : Place the pad 

 of filter paper (P) upon the glass disk (G) of the live-box; 

 lay the disk saturated with paraflBne (f), upon P , put the 



