352 Messrs. Schlossberger and Kemp o» /he Proportion of 



partment which has hitherto been so defective in the myst^m 

 rious doctrine of nutrition. ■ 



Already Boussingault and Liebig have demonstrated, that 

 in general the amount of proteine compound, and therefore 

 that of nitrogen, is in a direct ratio to the phosphates: this 

 proposition has as yet been extended only to vegetable mattersj>- 

 but will most probably preserve its value when applied like- 

 wise to those derived from animals. In so far as the nitrogen 

 may be taken as an indication of the quantity of these salts, 

 we could not find any observations as to how far it might be 

 also applied to the gelatigenous compounds ; and we have al- 

 hided to this as a very interesting field for future research, 

 particularly with regard to the phosphate of lime, which!^ 

 seems so universal and so necessary to the whole animal oeco-< 

 nomy. 



It seems to be at present a proper time to overcome an ob- 

 jection, which, if not alluded to, might have been made against^ 

 our attempt to determine the nutritive power of animal ali- 

 ments; it is with regard to the delicate question of the use of 

 animal gelatine, which seemed to Mulder, and likewise to us, » 

 as not at all decided by the experiments lately made at Paris. ' 

 It is a fact sufficiently proved by the experiments of Magendie, 

 Tiedemann and Gmelin, that any substance, even the most 

 nourishing, if very simple and used without admixture, cannot 

 sustain animal life for any length of time; and if it was proved 

 at Paris that dogs fed exclusively on gelatine perish, it is far 

 from being just to conclude that the substance is not nutri- 

 tive, as we should be compelled to apply the same rule to al- 

 bumen and fibrine, by the exclusive use of which an animal 

 would no less speedily perish. At all events gelatine has a 

 high value as nutriment, if even that value arises alone from 

 its being useful in the formation of gelatigenous tissues; in 

 addition, the gelatigenous tissues, as well as those containing 

 proteine, in regard to their formation and chemical constitu- 

 tion, seem to lie in close relation, although that relation is at 

 present not perfectly understood*. The experience of our 

 best physicians at the bedside of the patient tends to prove 

 that during convalescence a well-prepared gelatinous diet, but 

 not exclusively gelatinous, is highly nutritious. 



All organic alimentary substances, as presented to us by 

 nature, are mixtures, but seem to be pretty constant in their 

 composition, although variously modifiecl by our different 

 modes of cooking them. Of such natural mixtures, the 

 greater part taken from vegetable bodies have already had the 



* See Mulder's Chemistry of Animal and Vegetable Physiology, trans- 

 lated by Fromberg, 31 9 and following pages. 



