600 ORGANS OF GENERATION. 



matters, which also occur in the vegetable kingdom (THUDICHUM), and 

 whose relation to the vegetable pigments, the xanthophyll group, has 

 recently been shown by ScnuNCK, 1 have been called Interns or lipo- 

 chromes. 



The luteins, which among themselves show somewhat different proper- 

 ties, are all soluble in alcohol, ether, and chloroform. They differ from the 

 bile-pigment, bilirubin, in that they are not separated from their solution 

 in chloroform by water containing alkali, and also in that they do not give 

 the characteristic play of colors with nitric acid containing a little nitrous 

 acid, but give a transient blue color, and, lastly, they ordinarily show an 

 absorption-spectrum of two bands, of which one covers the line F and 

 the other lies between the lines F and G. LEWIN, MIETHE and STENGER 2 

 have given exact reports as to the absorption behavior of the lutein 

 from egg-yolk in various solvents. The luteins withstand the action of 

 alkalies so that they are not changed when we remove the fats present 

 by means of saponification. 



Lutein has not been prepared pure. MALY 3 found two pigments free from 

 iron in the eggs of a water-spider (Maja squinado) one a red (vitellorubin) and 

 the other a yellow pigment (vitellolutein) . Both of these pigments are colored 

 blue by nitric acid containing nitrous acid and beautifully green by concentrated 

 sulphuric acid. The absorption-bands, especially of the vitellolutein, correspond 

 very nearly to those of ovolutein. 



The mineral bodies of the yolk of the egg consist, according to PoLECK, 4 

 of 51.2-65.7 parts soda, 80.5-89.3 potash, 122.1-132.8 lime, 20.7-21.1 

 magnesia, 11.90-14.5 iron oxide, 638.1-667.0 phosphoric acid, and 5.5- 

 14.0 parts silicic acid in 1000 parts of the ash. We find phosphoric acid 

 and lime the most abundant, and then potash, which is somewhat greater 

 in quantity than the soda. These results are not, however, quite cor- 

 rect: first, because no dissolved phosphate occurs in the yolk (LIEBER- 

 MANN), and secondly, in burning, phosphoric and sulphuric acids are 

 produced, and these drive away the chlorine, which is not accounted 

 for in the preceding analyses. 



The yolk of the hen's egg weighs about 12-18 grams. The quantity 

 of water and solids amounts, according to PARKED to 471.9 p. m. and 

 528.1 p. m. respectively. Among the solids he found 156.3 p. m. protein, 

 3.53 p. m. soluble and 6.12 p. m. insoluble salts. The quantity of fat, 

 according to PARKE, is 228.4 p. m.; the lecithin, calculated from the 



1 Thudichum, Centralbl. f. d. med. Wissensch., 1869; Schunck, see Chem. Cen- 

 tralbl., 1903, 2, 1195. 



2 Pfliiger's Arch., 124. 



3 Monatshefte f. Chem. 2. 



4 Cited from v. Gorup-Besanez, Lehrbuch d. physiol. Chem., 4. Aufl., 740. 



5 Hoppe-Seyler, Med. chem. Untersuch., Heft 2, 209. 



