ORGANS OF GENERATION. 293 



essentially change the solubility and precipitating capacity of the 

 albuminous body, to wait for further investigations before we place 

 vitellin definitely in the globulin or nucleoalbumin group. 



The chief points in the preparation of ovo vitellin are as follows: 

 The yolk is thoroughly agitated with ether; the residue is dissolved 

 in a 10$ common-salt solution, filtered, and the vitellin precipitated 

 by adding an abundance of water. The vitellin is now purified by 

 repeatedly redissolving in dilute common-salt solutions and precipi- 

 tating by water. 



The yolk also contains, besides vitellin, alkali-albuminate and 

 albumin. 



The fat of the yolk of the egg is, according to LIEBERMANN, a 

 mixture of a solid and a liquid fat. The solid fat consists chiefly of 

 tripalmitin with some stearin. On the saponification of the egg-oil 

 LIEBERMANN obtained 40$ oleic acid, 38.04$ palmitic acid and 

 15.21$ stearic acid. The fat of the yolk of the egg contains less 

 carbon than other fats, which may depend on the presence of 

 mono and diglycerides or on a quantity of fatty acid deficient in 

 carbon (LIEBERMANN). 



Lutein. Yellow or orange-red amorphous coloring matters 

 occur in the yellow of the egg and in several other places in the 

 animal organism, for instance in the blood-serum and serous fluids, 

 fatty tissues, milk-fat, corpora lutea, and in the fat-globules of the 

 retina. These coloring matters, which also occur in the vegetable 

 kingdom (THUDICHUM), have been called luteines or lipocfiromes. 



The luteines, which among themselves show somewhat different 

 properties, are all soluble in alcohol, ether, and chloroform. They 

 differ from the bile-coloring matter, 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 give an absorption-spectrum of 

 ordinarily two bands, of which one covers the line F and the other 

 lies between the lines F and G. The luteines withstand the action 

 of alkalies so that they are not changed when we remove the 

 fats present by means of saponification. 



The lutein from the yolk of the egg has not been prepared in a pure state. 

 According to CHEVREUL and GOBLET, the yolk contains a partly red and part- 

 ly yellow pigment. MALY has found two pigments free from iron in the eggs 



