Chapter ^ 



Nitrocellulose 

 Method 



This form of embedding is often classified as the celloidin technic 

 and celloidin becomes something of a generic term inclusive of the 

 various cellulose compounds, such' as nitrocellulose and soluble gun 

 cotton or collodion. These are solutions of pyroxylin consisting chiefly 

 of cellulose tetranitrate. Obviously a purified nonexplosive form of 

 pyroxylin is necessary and there are several on the market: Parloidin, 

 Celloidin, and Photoxylin. (An excellent prepared embedding medium 

 can be purchased from the Randolph Products Co., Carlstadt, N.J., 

 "Tissue Embedding Solution :#:4700" — a solution of 30% low viscosity 

 nitrocellulose in 35% ether and 35% absolute ethyl alcohol. It is a 

 special low viscosity nitrocellulose (LVN) allowing more rapid infiltra- 

 tion with solutions of higher concentration than is possible with many 

 of the other so-called celloidins. This permits formation of harder 

 blocks in a shorter time and thinner sections can be cut than with the 

 latter types of media. 



The chief advantages in using the nitrocellulose method are that 

 larger and harder pieces can be cut in nitrocellulose than in paraffin, 

 and the consistency of nitrocellulose allows mixed (hard and soft) tis- 

 sues to be cut. This quality is useful for organs such as eyes, teeth and 

 bones and their surrounding tissues, and for problems of shrinkage and 

 the formation of artificial spaces. But a slow dehydration and prolonged 

 infiltration is preferred in these cases. Also the method is costly, 



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