42 GELATINE. CHONDRINE. [CHAP. I. 



cuticle and hairs by soaking in lime-water, are tanned by sub- 

 mitting them to the action of infusion of oak-bark, the strength of 

 which is gradually increased until a complete combination has taken 

 place. An insoluble compound is thus formed, capable of resisting 

 putrefaction. 



According to Mulder, gelatine contains in one hundred parts, 



Nitrogen .... 18-350 



Carbon . . . 50.048 



Hydrogen . . . 6*477 



Oxygen . . . 25125 



100-000 



to which may be added some inorganic material, chiefly phosphate 

 of lime. 



Dr. Prout remarks, that gelatine in animals may be said to be 

 the counterpart of the saccharine principles of plants ; it being dis- 

 tinguished from all other animal substances by its ready conver- 

 tibility into a sort of sugar, by a process similar to that by which 

 starch may be so converted. If a solution of gelatine in concen- 

 trated sulphuric acid be diluted with water and boiled for some 

 time, gelatine-sugar may be obtained from it, on saturating with 

 chalk. Again, by boiling gelatine in a concentrated solution of 

 caustic alkali, it is separated into leucine and gelatine-sugar, or 

 glycicott. The latter product crystallizes in pretty large rhomboidal 

 prisms ; is colourless, inodorous, and very sweet.* It differs from 

 sugar, however, in the important particular, that it contains nitro- 

 gen ; and Mulder assigns to it the following formula, C 8 H 7 N 2 O 5 

 + 2 HO. 



Proteine cannot be obtained from gelatine ; but it seems reason- 

 able to infer, that it or its compounds must have contributed to 

 the formation of the latter substance, for, in the egg, the gelatine 

 of the chick cannot be derived from any other material than a 

 compound of proteine. Scherer has shewn that gelatine contains 

 the elements of two equivalents of proteine, with three of ammonia, 

 and seven of water. 



5. Chondrine is a substance in many respects similar to gelatine. 

 It is obtained in a state of solution, by boiling water, from the 

 permanent cartilages and from the cornea; also from the temporary 

 cartilage prior to ossification ; it gelatinizes on cooling, and when 



* Graham's Chemistry, p. 1039. 



