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NUTRITION. 



We need scarcely observe that the excess of water in the excre- 

 tions, amounting to 6*615, corresponds to the water which is formed 

 by the process of respiration ; the augmentation of the salts is due 

 to the oxidation of sulphur. 



While our preceding observations have had reference to the 

 metamorphosis of tissue in full-grown animals, which are undergo- 

 ing neither an augmentation nor a diminution of their bodily 

 weight, we now proceed to the determination of those relations of 

 nutrition in which either the food is not sufficient to maintain the 

 normal weight of the organism and the energy of its functions, 

 or when an augmentation of the weight of the body, growth or 

 fattening, is going on. 



We can here include in a few words all that need be said regard- 

 ing the conditions which seem to render the nutriment insufficient 

 for a given organism, since the consideration of this point neces- 

 sarily arises from our previous remarks. The nutriment may be 

 insufficient either in its quantity or its composition. We have 

 already attempted, in so far as the present state of our knowledge 

 allows us, to answer somewhat in detail the question regarding the 

 quantity of food that is requisite to retain the organism in its 

 normal state; but we have not entered so fully into the question 

 regarding the quality of the food requisite to keep the body in a 

 thriving condition. Although the subject has been already noticed in 

 the preceding pages, and it might be concluded a priori from the 

 facts there laid down, that only such a nutriment could perma- 

 nently support the integrity of the organism, as contains all the 

 essential elements of food, namely albuminates, fats, carbo-hydrates, 

 and certain salts, it yet remains for us to mention the experiments 

 made by Boussingault, which yield a positive proof of the correct- 

 ness of these views. Even in what are now considered the older 

 works on physiology we find a description of the experiments of 

 Tiedemann and Gmelin, who failed in keeping geese alive on an 

 abundant diet of white of egg. The experiments made under the 

 direct observation of the Paris Academy on the questionable 



