846 METABOLISM. 



with organic phosphorus compounds, also indicate such a formation. 

 Other investigators, such as v. WENDT/ also admit of a synthesis of phos- 

 phorized protein substances by the aid of inorganic phosphates. 



Lack of Iron. As iron is an integral constituent of haemoglobin, 

 absolutely necessary for the supply of oxygen, hence it is an indispen- 

 sable constituent of food. Iron is a never-failing constituent of the 

 nucleins and nucleoproteins, and herein lies another reason for the 

 necessity of the introduction of iron. Iron is also of great importance in 

 the action of certain enzymes, the oxidases. In iron starvation, iron is 

 continually eliminated, even though in diminished amounts; and with 

 an insufficient supply of iron with the food the formation of haemoglobin 

 decreases. The formation of haemoglobin is not only enhanced by the 

 supply of organic iron, but also, according to the general view, by inor- 

 ganic iron preparations. The various divergent reports on this question 

 have already been given in a previous chapter (on the blood). 



In the absence of protein bodies in the food the organism must nourish 

 itself by its own protein substances, and with such nutrition it must sooner 

 or later succumb. By the exclusive administration of fat and carbohy- 

 drates the consumption of proteins in these cases is very considerably 

 reduced. According to the doctrine of C. VOIT, which has been defended 

 by recent investigations of E. VOIT and KoRKUNOFF, 2 the protein metab- 

 olism is never so low under these conditions as in starvation. Accord- 

 ing to several investigators, such as HIRSCHFELD, KUMAGAWA, KLEM- 

 PERER, SIVEN, LANDERGREN, and others, the protein metabolism may 

 indeed, with exclusively fat and carbohydrate diet, be smaller than in 

 complete starvation. Thus LANDERGREN has observed on an adult, 

 healthy man in nitrogen starvation but with sufficient supply of energy 

 (about 40 calories per kilo as carbohydrates and fat) on the fourth 

 starvation day that the nitrogen excretion was not more than 4 grams. 

 On the seventh day, with only carbohydrates, the nitrogen excretion 

 sank to 3.34 grams, which corresponded to 0.047 gram N per kilo of body 

 weight and to 0.29 gram protein. The recent investigations of MICHAUD 3 

 on dogs also show that in protein starvation, as by exclusive feeding 

 with fat and carbohydrate, lower results are obtained for the nitrogen 

 elimination than in complete starvation. 



The absence of fats and carbohydrates in the food affects carnivora and 

 herbivora somewhat differently. It is not known whether carnivora 

 can be kept alive for any length of time by food entirely free from fat 



1 Skand. Arch., f. PhysioL, 17. 



2 Zeitschr. f. Biologie, 32. 



3 Hirschfeld, Virchow's Arch., 114; Kumagawa, ibid., 116; Klemperer, Zeitschr. 

 f. klin. Med., 16; Sive"n, Skand. Arch. f. Physiol., 10 and 11; Landergren, l.c-., 11; foot- 

 note 3, page 837, also Maly's Jahresber., 32; Michaud, Zeitschr. f . physiol. Chem., 59. 



