Brande on the Separation of Jiiimal Substances. 287 



Art. VI. On the Separation of the Proximate Principles of 

 Animal Substances. Bj/ W. T. Brande, Sec. R.S., and 

 Prof. Chem. R.I. 



In certain analyses of animal products, as for instance in 

 ascertaining the relative proportions of albumen, gelatine and 

 water, in the different kinds of muscular fibre, it is frequently 

 difficult to deprive the substances imder examination of hu- 

 midity, without at the same time occasioning a partial decom- 

 position of the dry residue. Under these circumstances I have 

 availed myself with considerable advantage of the air-pump 

 vacuum, including a surface of sulphuric acid, and have been so 

 much struck with the rapidity and perfection of the process in 

 these cases, as to be induced to recommend it as a very satis- 

 factory and easy mode of depriving organic bodies in general of 

 their adhering moisture, I have for some time contemplated a 

 series of comparative experiments upon the varieties of mus- 

 cular fibre employed as food, and one material object in these 

 inquiries was to determine the actual quantity of nutritive mat- 

 ter contained in given weights of such products : as far as this 

 has been satisfactorily effected, I shall state the results, princi- 

 pally as illustrating the advantage of the method above men- 

 tioned of depriving the substances of water. 



500 grains of recently killed veal, free from fat, and cut into 

 small shreds, was exposed upon a metal plate to a temperature 

 of 212° until it ceased to lose weight, when it was found to have 

 sustained a loss :=: 375 grains. 



A similar portion of the same fibre, submitted to distillation in 

 a retort at the temperature of 212°, could not be so perfectly 

 dried, but the water which passed over had a peculiar smell, 

 and was rendered slightly turbid by solutions of nitrate of silver, 

 subacetate of lead, and corrosive sublimate : these solutions 

 were rendered much more turbid by the water which passed 

 off when the heat of the retort was elevated to 320°; so 

 that it would appear that although rapid desiccation at 212° 

 occasions but a slight change, exclusive of the separation of 

 v/ater, a partial decomposition ensues at temperatures between 

 X 2 



