SCIENCE. 



[N. S. Vol. XXII. No. 549. 



proportional to the exposed area of the 

 animal. 



Even in pathological conditions a re- 

 markable constancy of total heat produc- 

 tion is apparent. Thus in such typical 

 disturbances as angemia, diabetes, gout and 

 obesity, the general laws governing the 

 output of carbon dioxide, the absorption 

 of oxygen and the production of heat are 

 found to be the same as in health. In 

 fever the metabolism and heat production 

 increase and this to a certain extent on 

 account of the warming of the cells. In 

 exophthalmic goiter there is probably an 

 increase in metabolism, due to the chemical 

 stimulus of an excessive production of 

 iodothyrin in the thyroid gland, while in 

 myxoedema the absence of the same sub- 

 stance causes a considerable reduction in 

 the metabolism. Drugs may influence the 

 course of the metabolism, iodothyrin in- 

 creasing it and morphine profoundly di- 

 minishing it, but on the whole the most 

 striking fact is not the variability, but 

 rather the uniformity, of the processes con- 

 cerned. 



Within recent years the work of Kossel, 

 Fischer, Hofmeister and Levene has given 

 a more definite conception of the composi- 

 tion of proteid than was before possible. 

 There is every indication that the proteid 

 molecule consists fundamentally of groups 

 of amino fatty acids banded together. 

 Proteids vary with the integral components 

 of their chemical chains. It has long been 

 known that the end products of tryptic 

 digestion include such substances, but 

 Kutscher first showed that continued tryp- 

 tic digestion resulted in the complete trans- 

 formation of proteid into these amino-acids. 

 Cohnheim discovered erepsin, an enzyme 

 derived from the intestinal wall, which 

 rapidly converts albumoses into these sub- 

 stances. 



On chemical analysis, using methods de- 

 veloped in Emil Fischer's laboratory, the 



cleavage products of various proteids ap- 

 pear distributed as shown in the following 

 table.^ 



COMPOSITION OP PKOTEID. 



Glycocoll 



Alanin 



Leucin 



Pyrrolidin carboxylic acid 



Phenylalanin .". 



Glutamic acid 



Aspartic acid 



Cystin 



Serin 



Oxy-y-Pyrrolidin carbox. 



ylic acid 



Tyrosin 



Anninovalerianic acid 



Lysin 



Histidin 



Arginin 



Tryptophan 



3.8 

 3.6 

 20.9 

 1.7 

 2.4 

 6.3 

 4.5 

 0.25 

 0.33 



2.0 

 2.13 

 * 



2.0 

 1.0 

 11.7 



* Present. 



The proteid metabolism in plants and 

 animals occurs in striking similarity to the 

 changes brought about by enzymes and 

 hydrolytic agents acting on proteid out- 

 side of the tissues. Thus in the germin- 

 ating seed S^chultze^ finds that asparagin, 

 leucin, tyrosin, histidin, arginin and lysin 

 arise from the metabolism of proteid. The 

 occurrence of leucin and tyrosin in the 

 liver and urine in such diseased conditions 

 as phosphorus poisoning has long been 

 known and Abderhalden and Bergell* re- 

 port the presence of glycocoll in rabbit's 

 urine after the administration of phos- 

 phorus. Urine after phosphorus poisoning 

 may also contain phenylalanine and ar- 

 ginin.^ Wakeman'^ finds an altered quan- 



^ Abderhalden, E., Zeitschr. f. physiol. Ghem., 

 1905, Bd. 44, p. 17. 



^ Scliultze and Castero, Zeitschrift fiir physio- 

 logische Ghem., 1904, Bd. 44, p. 455. 



* Abderhalden and Bergell, Zeitschrift fUr 

 physiologische Ghem., 190.3, Bd. 39, p. 464. 



= Abderhalden and L. F. Barker, Zeitschrift fUr 

 physiologische Ghem., 1904, Bd. 42, p. 524. 



^Wohlgemuth, Zeitschrift fiir physiologische 

 Ghem., 1905, Bd. 44, p. 74. 



' Kossel, Berliner klinische Wochenschrift, 1904. 

 No. 41. 



