(•iii:mi.sti;\ (»k thi; vkast ckll nuclkin 167 



iiiilil t'xIiiiustiMl, toiuid thiit, of the 2.78 jji-ains of nitrofjeii 

 piL'soiit in 100 ^niiii.s of fifsh yen-st (coiitiiinin^ 30 per cvut. of 

 dry matter), 075 {;niiii couM lie extnu-teil in tlii.s uiauiier. In 

 distilliiiir fermented distillei y mash, a larj^er or smaUer amount 

 of the nuch'in of the c(»ntaine<l vea>t is similarly decomjMjseil, 

 so that the still residue eontains relatively little nuclein, liUt a 

 hirge amount of nuelein bases and free phosjthorie acid. This 

 fact must he kept in mind, not <jnly when the distillery residue 

 (from jiotato and giain distilleries) is used as fodder, hut also 

 when the same is used as a yeast food (in the manufaeture of 

 pressed yeast) and is ailded in a certain proportion to the mash, 

 a method which is found hy expel ieiice to result in an increased 

 yieUl and -(reatei- security in workinjj. 



A certiiin practical value, for the fotxlstuff chemist, attiiclies 

 to the I'eports on the decomposition products of yeiist nuclein, 

 in cases wheri* it is a tpiestion of ileterminin>: the purity of a 

 given meat extract and detectinj^ the presence of a sul'Stitute 

 preparetl from yeast. The (juantity of beer yeast annually 

 produced in the great brewing countiies has been approximately 

 estinuiteil by Feron at about 305,000 tons. Of this amount 

 about 132,000 tons have l.itlu'rto been utili.setl, partly for pitch- 

 ing in breweries and molasses distilleries, and partly us an 

 adidterant of pressed yeast. This leaves .still nn less than 

 173,000 t<jns unutilised; and many biewers have attempted to 

 find a nieans of putting this waste product to prolitiible use, 

 insteatl of letting it run away into the drains or water-courses 

 and thereby leading to constant complaints on the part of 

 ni'ighbours and local authorities. An endeavour has l>een made 

 to convert this surplus beer yeast, which is rich in proteids and 

 phosphoric acid, into preparations either capable of utilisation 

 as a yeast fix)d in the distillery (especially in mola.sses dis- 

 tilleries) instead of the usual addition of grain, or el.se for 

 huuum consinnption as a sul)stitutt« ft)r meat extnu-ts, or finally 

 as a concentnited cattle food. With this t)bject the yea.^t is 

 either converted into extnut, or is worked uji in its entirety 

 alone or with certain adjuncts. A number t)f proces.ses liave 

 been devi.st'd for working up yeast into nutritive preparations; 

 antl of these, mention may be made of the following foi- making 

 yeast extracts, viz. those of E. Baieii (II.), Gilliiaisex. K. Waul 

 and M. IIeniis (1.). K. Kkessel (I.), Pecteus (1.). .1. Cood- 



FELLOW (1.). T. HlM.-.JoNES and K. KuESSEI, (1.). K. .loHXSOX 



(I.), C. OSii.MVAN (i.), I). Watson (I.). A. Penavkk (1.). and 

 Lebiun (11). In the methotl of (!. Ek iiei.hai m (I.), yeast is 

 subjected to the action of species of Asft^'ri/illtt." before lixivia- 

 tion ; and according to that of O. (J. Oveuheck (1.) to the 

 inlluence of peptase from malt cuhus. The folh)wing methotls 

 deal with the ye;ist as a whole, without extniction : that of 

 Wegener, which is conceriunl with the jirtxhiction of a cofTee 



