INTRODUCTION. 15 



dry before applying another. When the specimen 

 has become completely covered, allow it to stand in 

 the air for half an hour, and then immerse it in 80 

 per cent, alcohol for twenty-four hours. This coagu- 

 lates the celloidin, and makes a firm semi-opaque mass. 



b. Imbed in a paper box. Boxes for this purpose 

 may be easily made in the following manner: Pro- 

 vide a series of rectangular wooden blocks, the faces 

 of which should correspond to the sizes of the boxes 

 wanted. Take one of these blocks and fold a piece 

 of paper over it, folding over* the corners, and then 

 folding down the portion of the paper that projects 

 above the surface of the block. Remove the block, 

 and the box is ready for use. Place the specimen in 

 the box, adjust it as to position, pour in celloidin 

 until the specimen is well covered, and as soon as a 

 firm pellicle has formed on the surface immerse the 

 box in 80 per cent, alcohol, and allow it to remain for 

 twelve hours. Now remove the paper from the solid 

 block of celloidin and mount it on a block of wood by 

 moistening its under surface with celloidin and 

 gently pressing it down on the block, allow it to 

 stand for ten or fifteen minutes in the air, and then 

 place in 80 per cent, alcohol, when, at the end of an 

 hour or two, the specimen will be ready for cutting. 



c. A box is made by winding a strip of paper 

 around a cork, allowing the paper to project an inch 

 or an inch and a half above the surface of the cork, 

 the paper being held in place by placing a rubber 



