462 NORMAL HISTOLOGY AND ORGANOGRAPHY. 



C. Advantages of Paraffin Imbedding. 



1. Accommodates very small objects. 



2. Thinner sections may be cut. 



3. Rapid process. 



4. Cheaper than celloidin method. 



D. Disadvantages of Paraffin Imbedding. 



1. Must use heat, which is injurious to 



tissues. 



2. Must remove paraffin to stain sections, 



and the latter therefore tear easily. 



3. Proper room temperature necessary 



when sections are cut, in order to 

 conform to melting-point of paraf- 

 fin. 



7. Cutting Sections. Use the whole edge of the 

 knife in cutting celloidin sections, and keep the 

 knife wet with 70% alcohol. When cutting paraf- 

 fin sections, the knife is placed at right angle to the 

 block. Always trim away superfluous paraffin. 



8. Staining celloidin sections. 



1. Alcohol, 95%. 



2. Water. 



3. Hematoxylin, ten minutes. 



4. Water. 



5. Acid alcohol, HC1 0.5 to i%; leave the 



sections in this until all stain is 

 washed out of the celloidin. 



6. Water. 



7. Eosin, 0.5% solution, one to three 



minutes. 



8. Alcohol, 35%. 



9. Alcohol, 95%. 



