Miscellaneous Intelligence. 



being closed, steam of common pressure is to be sent in, which at 

 first fuses the fat, and dissolves a little gelatine ; after this, the pres- 

 sure is to be increased. The liquids are to be withdrawn from the 

 cylinder by means of a cock placed below. The gelatinous solution 

 is obtained more or less concentrated, according to the slowness or 

 rapidity with which the steam is condensed, and the divided state of 

 the bones. The following are the points to be attended to. i. The 

 bones should be broken in small pieces, and the smaller in propor- 

 tion as they are more compact, more charged with fat, and require 

 to be freed from it the more rapidly, or at a lower temperature, 

 ii. The crushed bones should be previously freed from fat, either 

 by means of boiling water in common boilers, or in cylinders by 

 low pressure steam, or in water heated by steam, iii. The pressure 

 of the steam should be diminished, and the duration of the operation 

 increased, in proportion as it is required to obtain a purer and 

 stronger jelly, iv. It is most economical to prepare very strong 

 gelatinous solutions, which are afterwards brought to the proper 

 strength by boiling water: to obtain this result, care must be taken 

 to moderate the condensation in the apparatus, v. The degree of 

 pressure most convenient is that of 960 millimeters (37^ inches) of 

 mercury, corresponding to a temperature of 223° to 224°.5 F. 

 Stop-cocks placed on the vapour tubes serve to regulate the pres- 

 sure at will. 



The solution of jelly comes from the apparatus perfectly clear, 

 unless agitated by violent expulsion. Being without taste, it may 

 be sugared or flavoured at pleasure, for the preparation of table 

 food. Reduced until it contains only two hundredths of dry jelly, 

 it is equally charged with animal substance, as the best bouillon of 

 the kitchen, and will serve either to animalize vegetable food, or, 

 after being salted, coloured, and flavoured, to replace ordinary 

 bouillon. The salt which is most advantageous in giving it an 

 agreeable taste is, according to M. Braconnot, a mixture of 70 

 parts of common salt, and 30 chloride of potassium. If, after it 

 conies from the cylinder, it is flavoured with vegetables, or the juice 

 of meat and evaporated, gelatine or animal tablets are obtained. 



The fat in bones is easily saponified by the action of high pres- 

 sure steam; it is therefore better to separate it by boiling water, or 

 even in water at a lower temperature ; the fat is better the lower 

 the temperature has been. The fat is easily given out in vapour, 

 only slightly compressed, but the quantity saponified and remaining 

 as an insoluble compound with the lime, amounts sometimes to 

 four or five hundredths of the weight of the bones, which loss it is 

 desirable to avoid. 



An apparatus, consisting of four cylinders, has been put up at the 

 Hopital de la Charite\ Each cylinder is a metre (39.37 inches) in 

 height, one-third in diameter, contains about 40 kilogrammes of 

 bones, and gives about 1000 bouillons per day. — Ann. de Chimie, 

 xl. 422. 



