CHEMICAL COMPOSITION OF THE BODY. 



89 



are full of interest, in reference to the successive stages or plans of disin- 

 tegration suffered by the albuminous compounds in their passage through 



Kreatin. 



the body, since nearly all of them are found in one or other of the several 

 fluids or tissues. 



KREATININ, C 4 H 7 N 3 O, is usually associated with kreatin, and conse- 

 quently occurs in muscular and ner- 

 vous tissue, and in the blood and FIG. 47. 

 urine, but is not found in the gland- 

 ular textures. Nawrocki, 1 how- 

 ever, believes his experiments prove 

 satisfactorily that kreatiuin is not 

 a constituent of muscle, and that no 

 conversion of kreatiu into kreati- 

 uiu occurs during exercise. As 



just shown, it may be obtained from 

 the action of acids on kreatin. It 

 is a powerful base, and crystallizes 

 in oblique rhombic prisms, which are 

 soluble in water and in boiling al- 

 cohol. Kreatinin. 



LUTEIN. This term has been ap- 

 plied by Dr. Thudichum 2 to a yellow substance crystallizable in rhombic 

 plates, which can be obtained from various parts of animals and plants. It 

 is normally present in the vitellus of the egg, in the corpora lutea of the 

 ovary, and in the serum of blood, the cells of fat, and under pathological 

 conditions in ovarian tumors and in serous effusions. It is also contained 

 in the seeds, roots, leaves, and stamens of many plants. It is easily soluble 

 in alcohol, ether, and chloroform, but is insoluble in water. Its spectrum 

 presents three absorption bands in the blue, indigo, and violet portions of 

 the spectrum. It crystallizes and exhibits strong attraction both for fatty 

 and for albuminous substances. The substance termed Hsematoidin by 

 Holer and Stiideler is Luteiu ; but the Hamiatoidiu of Valentiner, Robin, 

 Ruhe, and Mercier is Bilirubin or Cholophifiin. 



URIC ACID, C 5 H 4 N 4 O 3 . When perfectly pure, uric acid appears in the 

 form of colorless, microscopic, rhombic crystals, occasionally in six-sided 

 plates, and sometimes in rectangular four-sided prisms; but as they are usually 

 seen in the urinary deposit of rheumatic patients, the angles of the rhombic 

 plates are rounded off' and stained, more or less deeply, by the coloring 

 matters of the urine. It is nearly insoluble in water, and completely so in 

 alcohol and ether. It is dissolved by concentrated sulphuric acid, and can 



1 Fresenius, Zeits. f. Analyt. Chcmie, Band iv, 2. 



2 Centralblatt, 1869, p. 1. 



7 



