CHAPTER X 
THE CELLOIDIN METHOD 
The celloidin method has almost disappeared from botanical 
microtechnic, because material too hard for imbedding in paraffin 
can be cut without any imbedding at all, and material too delicate 
to be cut without a supporting medium can be imbedded in paraffin. 
But these two categories do not cover all the ground; celloidin still 
has its advantages. Years ago, a piece of rotten wood from an ancient 
Egyptian mummy case was brought to the writer for identification. 
It could be rubbed into powder in the fingers, and had to be handled 
gently to keep it from falling to pieces. It was cut very successfully 
in celloidin. Stems too hard for paraffin may be cut in celloidin 
when it is desired to preserve cell contents. Celloidin is still very 
valuable for most of the sections used in medical schools, because the 
sections can be prepared in great numbers and each student can take 
a section, add a drop of balsam and a cover, and have a preparation 
of his own ready to study. Where serial sections are necessary, 
as in most morphological and cytological work, the method is too 
tedious to be worth even a trial, unless the sections cannot be cut 
in any other way. Besides, most of the more valuable stains color 
the celloidin matrix, and if the matrix be removed, the more delicate 
elements may be displaced or even lost. 
Celloidin and collodion are forms of nitro-cellulose. They are 
inflammable, but do not explode. Schering’s celloidin, which is only 
a collodion prepared by a patented process, is in general use for 
imbedding. Granulated and shredded forms of celloidin are on the 
market, but the tablets are more convenient. Directions for making 
the various solutions accompany the celloidin. To make a 2 per cent 
solution, add to 1 tablet enough ether-alcohol to make the whole 
weigh 2,000 g. To make a 4 per cent solution, add another tablet, 
and to make a 6 per cent solution, add an additional tablet, and so on. 
The collodion method was published by Duval 1 in 1879. Cel¬ 
loidin was recommended by Merkel and Schiefferdecker 2 in 1882. 
1 Duval, Journal de Vanatomie, 1879, p. 185. 
2 Merkel and Schiefferdecker, Archiv fiir Anatomie und Physiologie, 1882. 
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