114 Lecithin. I 
3.84. On the other hand, if both lecithin and cephalin possess 
the structure assigned to them by theory then the above mixture 
should have the elementary composition found by experiment. 
Thus the facts presented in this report furnish evidence in favor of 
the prevailing theory of the molecular structure of lecithin and 
of cephalin; they also indicate the method by which the pure re- 
duced cephalin may eventually be obtained. Efforts in this direc- 
tion are now in progress. 
_ In this connection it may be recalled that the product obtained 
on reduction of cephalin with hydrogen gas in the presence of 
palladium contained from 62 to 63 per cent of carbon in its 
molecule, thus approaching nearer than the non-reduced cephalin 
the theoretical value. ‘The non-reduced cephalin generally ob- 
tained is undoubtedly an altered and perhaps oxidized form of 
the original substance. The nature of the alteration is not known 
as yet. 
EXPERIMENTAL. 
Hydrolecithin was first prepared by Paal and Oehme;” they 
reduced an alcoholic solution of egg lecithin with hydrogen and 
colloidal palladium. The product was obtained as microscopic 
compact crystals, which sintered at 83-84°, and decomposed 
over 150° with blackening. Upon hydrolysis the hydrolecithin 
gave a mixture of stearic, palmitic, and probably myristic acids. 
The following year Ritter® reduced lecithin which had been pre- 
pared from fresh, dry egg yolk as follows: The egg yolk was 
first extracted with petroleum ether and then with ether; the 
ethereal extract was concentrated and the residue was then 
extracted with methyl alcohol. The hydrolecithin prepared in 
this way proved to be distearylhydrolecithin; that is, on einer 
ysis it yielded only stearic acid. 
Hydrolecithin has been prepared in our laboratory, by Paal’s 
method, from various fractions of egg lecithin, and from lecithin 
of brain and other organs. During the course of the work it 
has been noted that lecithin, which has been washed according 
to MacLean’s’ method, in which the lecithin is ground up with a 
little water and precipitated with acetone, is reduced more rap- 
idly and more completely than unwashed lecithin. Also, it was 
11 Paal, G., and Oehme, H., Ber. chem. Ges., 1913, xlvi, 1297. 
