Prof. Liebig on the Formation of Fat in the Animal Body. 19 



degree, about 20 per cent, being sufficient in either case to 

 destroy the colour of those metals. 



The uses to which the alloys of palladium have been ap- 

 plied, are for the points of pencil-cases, for lancets for vacci- 

 nation, for the graduated scales of instruments, as a substitute 

 for gold in dental surgery, or for any purpose where strength 

 and elasticity, or the property of not tarnishing, is required. 



VII. On the Formation of Fat in the Animal Body. 

 By Justus Liebig, Ph.D., M.D., F.R.S., $c* 



T N my published work on ' Organic Chemistry, in its ap- 

 ■■■ plication to Physiology and Pathology,' I have endea- 

 voured to explain the nutrition of the human and animal 

 organism, according to the present state of organic chemistry. 

 I have pointed out the relation between the nitrogenous food 

 and the nitrogenous constituents of animal bodies, and have 

 considered the non-nitrogenous constituents of the food as the 

 means of the formation of the non-nitrogenous constituents 

 of animals. 



The circumstance, that the large class of carnivorous ani- 

 mals do not take any sugar, starch, or gum in their food, leads 

 of itself to the opinion that these substances are not required 

 for proper nourishment, namely, for the formation of blood; 

 and as it appears from the analysis of plants containing nitro- 

 gen, that they possess a similar composition to the substances 

 of the blood, it follows also that in the bodies of herbivorous 

 and graminivorous animals, the carbon of the sugar, gum and 

 starch cannot be applied to the formation of the blood. The 

 nitrogen of the nitrogenous ingredients of the food is therefore 

 in a state of combination, in which the elements necessary for 

 the production of the albumen are already present both in 

 number and relative proportions ; in the food of the gra- 

 minivorous animals, we know after all of no other compound, 

 which can supply nitrogen to starch, sugar, or gum, for the 

 production of albumen. 



As sugar, gum and starch, in their normal state, disappear 

 in the vital processes of graminivorous animals, and as they 

 are given out of their bodies as carbonic acid and water, it 

 follows from such a conversion that they serve by means of 

 the respiration for the production of animal heat. 



The disappearance of fat in animals in consequence of 



* Translated from the German original by Mr. E. F. Tesehemacher, and 

 communicated by the Chemical Society; having been read January 3, 1843. 

 On the subject of this paper see a translation of M. Dumas' s memoir On 

 the Chemical Statics of Organized Beings, in Phil. Mag. S. 3. vol. xix. 



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