MINERAL CONSTITUENTS OF THE ANIMAL BODY. 411 



Since we have made a practice of incorporating the methods of 

 qualitative and quantitative analysis in the description of the organic 

 substrata, it might naturally be expected that we should in like 

 manner enter into a special consideration of the different methods 

 for analysing the ash ; but however important this subject may be, 

 both in itself and in reference to physiology, we have, nevertheless, 

 been deterred by many reasons from adhering to this rule in the 

 present case. Thus, for instance, if we were once to enter 

 thoroughly within the domain of inorganic chemistry, we should 

 far exceed the limits assigned to this work, more especially if we 

 were definitely to refer to, and critically to illustrate, the different 

 methods for the analysis of the ash and the determination of indi- 

 vidual constituents ; nor could we indicate any one method as the 

 best, since different objects demand different methods. We, more- 

 over, entertain the frequently expressed but rarely practised view 

 that the study of physiological as well as of organic chemistry 

 generally, should be based upon an exact knowledge of inorganic 

 chemistry in all its relations, for many of the deficiencies which we 

 have found occasion to notice in the researches of zealous physio- 

 logical and pathological chemists are referable to an inadequate 

 knowledge of inorganic chemistry. We are, therefore, the more 

 resolved to omit all notice of the analyses of mineral substances, 

 again referring our readers to the admirable memoirs which have 

 appeared in recent times on this subject, and for which we are in- 

 debted to Will and Fresenius,* Mitscherlich,t Knop,{ Erdmann, 

 Heintz||, Rose^[, [and Strecker.** G. E: D.] 



If we venture to adopt a physiological classification in our 

 description of the mineral substances of the animal body (which, 

 moreover, can refer only to their physiological function,) we adopt 

 this course simply from a feeling of its great applicability, and 

 not because we consider ourselves able to indicate the exact 

 place occupied in this system by each individual mineral substance; 

 for the remarks we have already made, must sufficiently indicate the 

 uncertainty and deficiency of our knowledge on this subject. We 

 therefore attempt to divide the mineral substances of the animal 

 body in reference to their physiological importance, into : 



* Ann. d. Ch. u. Pharm. Bd. 50, S. 363-396. 



t Ber. d. Akad. d. Wiss. z. Berlin, 1845, S. 236-252. 



t Journ. f. pr. Ch. Bd. 38, S. 14-47. 



Ibid. Bd. 38, S. 40-69, and Ber. d. Gesellsch. d. Wiss. zu Leipzig, 1847, S. 83-90 . 



|| Op. cit. 



IF Op cit. 



** Ann. d. Ch. u. Pharin. Bd. 73. 



