156 



The Preparation of Microscope Slides 



Table 2 (Continued) 

 Defects Appearing while Sections Are Being Cut 



Defect 



Fig. 121. Sections bulge 

 in middle. 



Possible causes 



Remedies 



Wax cool in center, warm 

 on outside 



Only sharp portion of knife 



is that which cuts center of 



block 



Object impregnated with 



hard wax and embedded in 



soft, or some clearing agent 



remains in object 



3. 



Allow block to adjust to 

 room temperature. This is 

 the frequent result of cool- 

 ing blocks in ice water 

 Try another portion of 

 knife-edge or resharpen 

 knife 

 Reembed object 



Fig. 122. Object breaks 

 away from, or is shat- 

 tered by, knife. 



1. If object appears "chalky" 

 and shatters under knife 

 blade, it is not impregnated 



2. It object shatters under 

 knife but is not chalky, it 

 is too hard for wax sec- 

 tioning 



3. If object pulls away from 

 wax but does not shatter, 

 the wrong dehydrant, clear- 

 ing agent, or wax has been 

 used 



1. Throw block away and 

 start again. If object is 

 irreplaceable, try dissolv- 

 ing wax, redehydrating, re- 

 clearing, and reembedding 



2. Spray section between each 

 cut with celloidin 



3. Reembed in suitable me- 

 dium, preferably a wax- 

 rubber-resin mixture. Avoid 

 xylene in clearing muscular 

 structures 



1. Nick in blade of knife 



2. Grit in object 



Fig. 123. Ribbon splits. 



Try another portion of 

 knife-edge 



Examine cut edge of block. 

 If face is grooved to top, 

 grit has probably been 

 pushed out. Try another 

 portion of knife-edge. If 

 grit still in place, dissect 

 out with needles. If much 

 grit, throw block away 



