630 ORGANS OF GENERATION. 



sosaccharic acid. It is difficult to state whether this glucosamine was 

 derived from the vitellin or from some other constituent of the yolk. 



The principal points in the preparation of ovovitellin are as follows: 

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

 a 10-per cent common-salt solution, filtered, and the vitellin precipitated 

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

 edly redissolving in dilute common-salt solutions and precipitating with 

 water. 



Ichthulin, which occurs in the eggs of the carp and other, fishes is, accord- 

 ing to KOSSEL and WALTER, an amorphous modification of the crystalline body 

 ichthidin, which occurs in the eggs of the carp. Ichthulin is precipitated on 

 diluting with water. It was formerly considered as a vitellin. According to 

 WALTER it yields a pseudonuclein on peptic digestion; and this pseudonuclein 

 gives a reducing carbohydate on boiling with sulphuric acid. Ichthulin has the 

 following composition; C 53.42, H 7.63, N 15.63, 22.19, S 0.41, P 0.43 percent. 

 It also contains iron. The ichthulin investigated from codfish eggs by LEVENE 

 had the composition C 52.44, H 7.45, N 15.96, S 0.92, P 0.65, Fe+0 22.58 

 per cent, and yielded no reducing substances on boiling with acids. The pure 

 vitellin isolated by HAMMARSTEN from perch eggs had a similar behavior and 

 was very readily changed by a little hydrochloric acid so that it was converted 

 into a typical pseudonuclein. The codfish ichthulin yielded a pseudonucleic acid 

 with 10.34 per cent phosphorus, but this acid still gave the protein reactions. 

 MCCLENDEN l has prepared a vitellin from frogs' eggs which he calls batrachiolin. 



The yolk also contains albumin, besides vitellin and the above-men- 

 tioned proteins. 



The fat of the yolk of the egg, LiEBERMANN 2 claims, is a mixture of 

 a solid and a liquid fat. The solid fat consists principally of tripalmitin 

 with some tristearin. On the saponification of the egg-oil LIEBERMANN 

 obtained 40 per cent oleic acid, 38.04 per cent palmitic acid, and 15.21 

 per cent stearic acid. The fat of the yolk of the egg contains less carbon 

 than other fats, which may depend upon the presence of monoglycerides 

 and diglycerides, or upon a quantity of fatty acid deficient in carbon 

 (LIEBERMANN). The composition of yolk fat is dependent upon the 

 food, as HENRI QUES and HANSEN 3 have shown that the fat of the food 

 passes into the egg. 



The phosphatides of the yolk seem to be of various kinds. THIER- 

 FELDER and STERN have found three different phosphatides. One of 

 these, which was soluble in alcohol-ether, behaved like lecithin. The 

 second was soluble with difficulty in alcohol, but readily soluble in ether, 

 contained 1.37 per cent N and 3.96 per cent P. The third was a diamino 



1 Walter, Zeitschr. f. physiol. Chem., 15; Levene, ibid., 32; Hammarsten, Skand. 

 Arch. f. Physiol., 17; McClenden, Amer. Journ. of Physiol. 25; see also .Plimmer 

 and Scott, Journ. Chem. Soc., 93. 



2 Pfliiger's Arch., 43. 



* Skand. Arch. f. Physiol., 14. 



