218 Specific Examples of Slide Making 



knife is sharpened in the manner previously described, the block is 

 mounted. This process has been described in some detail and need not be 

 repeated here. The block having been trimmed to size and mounted, there 

 remains only the actual cutting. The handle of the microtome should now 

 be rotated rapidly and the beginnings of the sections observed. There is 

 no need to worry if the section curls to one side or the other during this 

 preliminary period since the entire thickness of the block will not be 

 cut until 20 or 30 sections have been removed. As soon as the knife is seen 

 to be approaching the object and the block in its entirety is being cut, 

 the ribbon must be observed most carefully to see that it is suffering from 

 none of the common defects indicated in Table 2. Should the ribbon not 

 be coming perfectly, various suggestions given in Table 2 may be tried 

 until a perfect ribbon is obtained. Since, in this case, a series of sections 

 is not needed, it is unnecessary to cut a longer ribbon than one that will 

 contain the actual number of sections required, with a few left over for 

 emergencies. However, it is a great mistake to throw away partially cut 

 blocks of this nature since they may be stored indefinitely, and one never 

 knows when further sections may be required. The block should be 

 labeled before being placed in its solution. This is easily done by writing 

 the appropriate label on a piece of paper and fusing this into an un- 

 wanted portion of the block with a hot needle. 



Each individual section is now cut from the ribbon and mounted on the 

 slide in the way described in Chapter 12. Before actually using Mayer's 

 albumen to mount the sections, it is necessary that the slides be cleaned. 

 No two people have ever agreed as to what is the most desirable method 

 of doing this. The author rubs the slide briskly with 1 per cent acetic acid 

 in 70 per cent alcohol and dries it by waving it in the air. Another method 

 of cleaning the slide, which yields equally good results, is given in Chap- 

 ter 11. After the sections are cut, several drops of the diluted adhesive are 

 placed in the center of each slide. One of the individual sections is taken 

 up with the tip of a moistened brush and placed on the adhesive. As soon 

 as the section has been placed on the fluid, the slide is lifted up, warmed 

 carefully over a spirit lamp until the section is flat but the paraffin not 

 melted, and then the superfluous liquid removed carefully with the edge 

 of a filter paper. The slide is put in a warm place to dry. If the drying 

 period is to be prolonged, it is well to place a dust cover over the slide 

 since grains of dust falling upon it will adhere just as tenaciously to the 

 adhesive used as will the specimen itself. 



It is proposed in the present example to stain the slide in the simplest 

 possible manner with celestine blue B followed by eosin. The formulas 

 for these stains will be found in Chapter 7. Of course, any of the other 

 dyes recommended there may be substituted. 



When the section is perfectly dry, it is turned upside down, and light is 



