ON THE MAKING OF GELATIN CASTS. 



J. W. ScoM.icK, Frcparator. 



Ill uiidntiikiiij;' tlic prcpaiation of a scries of Mie \aiioiis breeds ol 

 doinestii'. fowls lor the I J. S. National IMiiseiiiii, it was iice(\ssary at the 

 outset to solve the i)ro])leiii of i'ei)la('iii.u the natural eomlts by arlilieial 

 ones since the natural combs when diied are so much distorted IVom 

 shi'inka.u'c as to seriously detract Croni the api»carauce of the moulded 

 specimens. 



Since no modeling', however skillful, can Liixc tiie exact a.i>pearan<*e 

 and i)attcrn of the pai)ill:c with which the cond) of ii- fowl is covered, it 

 seemed desirabU^ that- tlie artilicial cond) shoidd be cast in a mold 

 made from the. natural one. T'or the cast itself some durable material 

 was lu'.eded that (;ould \w rea-dily worked and easily colored, and was 

 capable of resisting' chanj>('sol' temperature. 



While wax possesses tlu^ iirst two (pialihciitions, an<l is, from its 

 tninslueeut cliaracter, very effective tor combs and wattles, yet cold 

 renders it brittle and the heat of a- Washinj^ton summer causes it to 

 Molten aud lose shape, it is, therefore, unsuitable foi' the i)uri)ose. 



Preparations with lilue (or gelatin) for their basis having;' been used 

 successfully for anatoiincal models, cast of lishes, etc., it seemed prob- 

 able that this substance could be employed with advantage for artili- 

 cial cond)S. After eonsidei'able experiuientiujn' the following- combimi- 

 tion was ibmul to i;ive <;()od results: 



OlllKCS. 



IJcst Iiisli gliiii 1 



Goliitiu* , 2 



({lycciiii 1 



Hoi led linseed oil \ 



The fj;lu(^ and ;;('latin should be softened in (JO per e(^nt alcohol, only 

 enoujih beinj;' used to barely cover them. The object of this is to in- 

 troduce as little water as possible into the compound. t 



The j;lue should then be melted aud the {iiycerin stirred into it, to- 

 gether with a few drops of carbolic acid or oil of cloves. 



( 'asts made of the above material ha\'e lain ex[>osed to the sun for 



*A stronj; gelatin Hiieli tis is u.scd liy iiliotoLiiiiplicrs is Ix'.st. 



t Otlior MH^tliddH may ho followed, however, siudi as wctliiij^ the j;liie and wra]>i»inn- 

 it in a moist <doth. 



rrocfodiiiUH Natioiiiil Muscimi, \'ol. X\I — Ni>. 1)20. 



61 



