1921] TYRRELL, CELLULOID AS A MODELING MEDIUM. 105 



Similarly, instructive exhibits are made of fresh-water species, 

 but here we have an opportunity to serve especially the great num- 

 bers of fishermen who frequent the thousands of Wisconsin lakes 

 yearly. 



A careful study of such exhibits is in itself a most valuable 

 lesson in conservation. 



CELLULOID AS A MODELING MEDIUM 



By E. R. Tyrrell"^ 



It is well known that celluloid is l^eing generally used in the 

 manufacture of many articles of various kinds, both useful and 

 ornamental, and nearly every one possesses one or more articles 

 made of this material. 



The work in celluloid is both fascinating and surprising, and 

 this medium is. the writer Ijelieves, most decidedly adaptable to 

 the modeling in which the present experiments are being conducted. 

 The first efforts in this direction were made in the hope that this 

 material might, in a measure, be used as a substitute for glass, 

 from which many very wonderful and beautiful models have been 

 produced. However, glass models are at the l)est very fragile and. 

 except in a few instances, the results might have been enhanced 

 by the substitution of celluloid. 



By the use of hot metal matrices, some of the simpler forms 

 were successfully pressed out. These answered their purposes 

 fairly well but were decidedly lacking in finish and perfection. The 

 process too, proved rather slow, and at times somewhat painful. A 

 solvent for this material was then sought. In the first trial (that 

 of dipping the celluloid in an acid bath) it was discovered that it 

 responded all too readily to the treatment and left only a quantity 

 of clear lacquer, in itself a very useful article, but not just what was 

 sought. However, it was possible to control this suddenness, and 

 with a little patience and perseverance a point was reached where 

 the material could be softened and stretched in all directions, much 

 like a sheet of rubber, in itself a most interesting feature. Taking 

 advantage of this discovery, small models were then produced and 

 it was realized that there had been made a marked advance and im- 

 provement in both method and results. 



^'Modeler, Department of Lower Zoology, Milwaukee Public Museum. 



