MINERAL CONSTITUENTS OF THE ANIMAL BODY. 407 



the presence of organic substances, owing to their inconsiderable 

 quantity in these extracts, will exert less influence on the decom- 

 position of the salts during incineration. In order as much as 

 possible to avoid the influence of the carbon and of the phosphates, 

 during the process of incineration, on the carbonates, I have been 

 in the habit of not exposing the whole of the carbonaceous residue 

 originally obtained from the organic substance to entire combustion, 

 but of reducing it to a small bulk over a gentle fire with free access 

 of air. The carbonaceous ash is then extracted with water and 

 hydrochloric acid, and the quantitative determination of the ash is 

 obtained by weighing and subtracting the residuary charcoal. But, 

 although I have certainly obtained more correct results by this 

 method than those yielded by the majority of previous analyses of 

 ash, it is nevertheless not free from error, nor can it be said to 

 afford an entirely satisfactory insight into the nature of the mineral 

 substances existing preformed in animal bodies. Fortunately for 

 science, H. Rose*, one of the most distinguished analysts of our 

 day, has entered upon this hitherto unpromising subject, and by a 

 series of the most carefully conducted investigations has obtained 

 important results, which are in part of a purely physiological cha- 

 racter. One of the most important facts ascertained by these 

 successful researches in analytical chemistry is, that in the animal 

 or vegetable substance perfectly carbonised by heat, there is usually 

 a greater or lesser quantity of alkaline and earthy salts, which cannot 

 be removed from the carbonaceous mass, even by the most pro- 

 longed extraction either with water or acids. These mineral sub- 

 stances must therefore be contained in the carbonised residue in a 

 different condition from those which admit of being removed by 

 various menstrua. Rose, therefore, concludes that such substances 

 as alkalies, earths, metals, phosphorus, sulphur, &c., must be con- 

 tained in the carbonaceous mass in a non-oxidised state, and in 

 combinations with which we are still unacquainted : he also thinks 

 that it may be assumed that such combinations of potassium, 

 sodium, calcium, iron, phosphorus, and sulphur, also exist pre- 

 formed in organic substances, since on the one hand the carbonisa- 

 tion of organic substances free from ash (as for instance sugar) 

 with the ordinary constituents of the ash did not yield any carbo- 

 naceous residue that could not be perfectly freed by the ordinary 



* Pogg. Ann. Bd. 70, S. 449-465, Berichte der Akad. der Wiss. zu Berlin, 

 Decbr. 1848, S. 445-462, and Pogg. Ann. Bd. 76, S. 305-404. [The last of these 

 memoirs is translated in the London, Edinburgh, and Dublin Philosophical Maga- 

 zine. New series, vol. 35, pp. 1, 171, and 271. G. E. D.] 



