Embedding 



18 



20 



21 



Figures 18, 19, 20, and 21. PYeparaUon of a fiber block and nitrocellulose 

 tissue block for sectioning. 



Rapid Method 



This method Avill not form as perfect a block as the former one; the 

 nitrocellulose is not ahvays uniform and may section unevenly. 



W'rap paper around the fiber block as for the slow method. Fill the 

 cavity with some nitrocellulose from the infiltrating jar and transfer 

 the tissue into the mass of nitrocellulose. Orient the piece of tissue so 

 it can be sectioned along the upper siuface. Set the fiber block and 

 nitrocellulose and tissue in a tightly capped jar with a small amount of 

 chloroform. Leave in this situation until the block is firm, but check 

 frequently to see that the chloroform does not evaporate completely. 

 When the nitrocellulose has hardened, add more chloroform to com- 

 pletely immerse the block and tissue until ready to section. 



Mounted or unmounted tissue blocks can be stored in chloroform, 



