THE REPRODUCTION OF FISHES IN PLASTER 231 



For all methods of making moulds or models of any object, 

 whether by means of plaster of Paris or of any other medium, 

 the first thing to be provided is — 



The Casting-box 



Leuckart's embedding-boxes ^ have given the writer an 

 idea for an improvement, not, perhaps, on the embedding-boxes 

 for their especial purpose, but on the ordinary casting-box, and 

 this is made in a more simple manner, whilst doing, more 

 efficiently, the work for which it is intended. Take, therefore, 

 four pieces of one-inch wood of any suitable length and 

 width — say two feet, or two feet six inches, in length — 

 two of them an inch or so wider than the others. At about 

 an inch from one end of each of the wider pieces cut a slot 

 just large enough to allow one of the narrower pieces to easily 

 pass through it, and, inserting one of the latter into each slot, 

 place the opposite ends of the narrower pieces at right angles 

 to the inner faces of the wider pieces, so as to form a rect- 

 angular box, every side of which is movable, and whose length 

 and width may be varied at will — limited only by the extreme 

 length of the sides — by sliding the narrower pieces through 

 the slots, and their other ends along the faces of the wider 

 pieces. 



It is necessary, be it observed, to oil the insides of the walls, 

 and also to place, along the bottom edges and corners, some 

 putty or clay to prevent the liquid plaster from running out. 



Direct plaster casting is the easiest to manage, and is the 

 system most in vogue. It consists in laying down some 

 natural object — say a snake or a fish, as being the easiest — and 

 pouring plaster over it until a mould or cast is made therefrom 

 in the manner now described. 



^ Journ. Roy. Mic. Soc. [N.S.], ii. p. 880 (see Microtomisfs Vade-mecum, Lee, 

 p. 172). 



