174 CHEMISTRY OF THE YEAST CELL. 



acid and palmitic acid (in almost equal amounts), along with a 

 small quantity of butyric acid, part of the acid being in the 

 free state and part combined with glycerin. The chief seat 

 of the fat is in the granules, whose albuminous membrane 

 prevents lixiviating fluids gaining access to the enclosed fat. 

 Consequenth', as remarked by Ntegeli and Loew, a simple 

 treatment with ether is ineffectual. Still less likely to effect 

 extraction is the small amount of alcohol present in wine ; and, 

 in fact, as shown by Mueller-Thurgau (XVIIL), wine does not 

 contain more than about o. i gram of fat per litre. In a case ob- 

 served by H. Will (YIII.) in 1898, drops of fat were found in 

 both dead and living cells and spores of a ten years old culture 

 of Sacch. Ludioujii in beer wort, their colour being reddish- 

 yellow, so that the culture gradually became of a brick-red 

 shade. 



A substance closely allied to the fats, namely lecithin, which 

 is the cholin ester of palmito-stearo-glycerophosphoric acid, and 

 is therefore constituted in accordance with the formula : — 



(C13H31COO) (Ci7H33COO):C3H5-0- PO.OH- C - CHo.CH.iNlCHslsOH 

 Palmitic Stearic Glycerin. Phosphoric Cholin, 



acid. acid. acid. 



was first discovered in yeast by Hoppe-Seyler (IY.) in 1866. 

 It was afterwards prepared by him (Y.), to the extent of 0.25 

 gram from 81 grams of air-dry pressed yeast, in the course of 

 I'ebutting a contrary opinion launched by 0. Loew (YIII.) and 

 IST^GELi and Loew (II.). 



The first discovery of cholesterin in fungi was made in 1867, 

 by O. KoHLRAuscH (I.), in a species of Morel; and -soon after- 

 wards it was found by Hoppe-Seyler (IY. ) in yeast. Later on, 

 this same worker (Y.) recovered 0.44 gram of this monovalent 

 alcohol (C.jjH^o.OH) from 81 grams of air-dry pressed yeast. 

 The name cholesterin, which was originally bestowed on a 

 single substance of animal origin, afterwards became enlarged 

 to a collective term, in consequence of the discovery of several 

 isomeric and homologous cholesterins, which, tliough agreeing 

 with the first cholesterin (from gall, ttc.) in their chief pro- 

 perties, yet behaved differently in several reactions. Thus, 

 Hesse isolated from peas the cholesterin to which he gave 

 the name phytosterin ; Reinke and Rodewald another (para- 

 cholesterin) from AethaUum sepficiun ; C. Tanret (IY.) a 

 third (ergosterin), from ergot of rye. According to the re- 

 searches of E. Geuard (III.-Y.), these latter are identical with 

 all the cholesterins hitherto isolated from yeast, as also from 

 Mucor mucedo, Penicillium glaucum, Staj^hylococcus albut>, and 

 indeed from Crypfotjams generally. 



