RECORDS. 



121 



This book must not be lost or misplaced. The advantage of having the serial 

 number written also on the bottle containing the stock of preserved material is very 

 evident if a thing of this sort ever happens. The serial number is written on one 



edge of the slide-box, and serves to identify it (fig. 103). 



Some record besides a mere number should also be placed 

 on the slide-boxes. All the slides within bear this num- 

 ber, e. g., 256, and also a 

 series number of their own, 

 /. e., i to 25. The slide- 

 boxes are then filed away 

 on shelves either serially 

 or in groups, according to 

 the parasite. Slides con- 

 taining particularly good 

 fields are marked X, and when the best fields are 



Fig. llO.t 



finally decided upon their location is recorded as de- 

 termined on the mechanical stage. In case a dozen 

 or more serial sections are included on one slide the 

 the extra good ones are marked X on the first exam- 

 ination, and the others 0, as shown in fig. 113. 

 When one of these sections has been drawn or photo- 

 graphed, the X is underscored or inclosed by a circle. 

 This method enables one to keep track of any num- 

 ber of sections. Free-hand sections may be made with the Torrey razor shown in 

 fig. ii4D. This is altogether the best razor the writer has used. When very 

 dull it may be sharpened on an India oil-stone. These stones are said to be made 

 of a mixture of carborundum and clay, baked at a high temperature. They may be 



Fig, Ill.t 



had of the Norton Emery Wheel Company, Worcester, Mass., in three grades of fine- 

 ness, the finest being usually coarse enough for the dullest razors. The size needed 

 is 8 by 2 by i inch. The finishing may be done on an Arkansas oil-stone, with a 



*FlG. 109. Coplin's staining jar. About one-half actual size. 



fFic. no. Cross-section of Coplin's staining jar. About actual size. 



|Fic. in. A series of Coplin's jars filled and properly arranged for staining sections fastened 

 to slides. 



