M. D'Arcet on the. Bones of Butcher's Meat. 295 



then increase the tension* The hquids are drawn off the cy- 

 linder by means of. a cock [placed at one end; the gelatinous 

 solution is obtained more or less concentrated, according to' 

 the rapidity of the condensation of the steam and the small- 

 ness of the bones. The following are the principal circumstances 

 which it is necessary to observe, — 



1st, The bones ought to be broken in thin pieices; and they' 

 should be bruised more if they are thick and full of fat ; and 

 they ought to be drained more rapidly, or at a lower tempe-" 

 rature. 



M, The broken bones ought to be deprived of their fat pre- 

 viously, either by means of boiling water in a common boiler, 

 or else in the cylinders, introducing steam not condensed, or 

 perhaps by water heated by means of steam. 



Qd, The steam of the water ought to be as much condensed, 

 and the period of the operation as much more prolonged, in 

 proportion as we would wish to obtain the gelatine pure, and 

 of a stronger jelly. 



4^/^, There would be more economy in preparing the gela- 

 tinous solution much concentrated, and then bringing it back 

 •to a convenient strength, by mixing it with hot water. To obi- 

 tain this result, care must be taken to moderate the conden-' 

 sation of the steam in the apparatus. 



5thy The degree of tension which best suits the steam is 

 that of 960 milimetres of mercury, which corresponds with 

 a temperature of 106 to 107 degrees. Cocks placed upon 

 the pipes which conduct the steam into the apparatus allow 

 the tension to be varied at will, and to be maintained uni^ 

 form. 



The solution of gelatine comes from the apparatus perfectly 

 clear, if it does not rush out impetuously with the steam. As 

 it is without flavour, it can be used as an alimentary jelly, 

 by the addition of sugar or aromatics at convenience. Re- 

 duced till it contains only two centiemes of dry gelatine, it is 

 as much impregnated with animal matter as the best household 

 soup, and may be used either to animalize all food of a vegetable 

 nature, or as a substitute for the soup after being salted, co- 

 loured, and aromatized. The salt which gives the most 

 agreeable flavour, according to the interesting remarks of M. 



