;unl between 70 ('. and tlie [mint at wliicli tlic lutivity uf tlir ni.ilt iliastasu is 

 (k'stniyi'd, the reaction is cxprcsseil li}' ecjiiation (', 



c. (;(C'-H,„o,„) + UD = o'-ii.„u„ n r)C'-H,„o,„ 



Siiliililo-starcli ]\fiillo<:- <'-iU'xlnii. 



Brown and Ilemn ann/e u itli ()"Snlli\an in lindinj^ only lnaltlls^• and dextrin 

 as tiie iinnliK'ts nl' tlie aetiDU of malt rxtraet upon stareli, l)ut their experiments 

 lead them to represent the proportions lornied at dilVerent teinp(;ratures a little 

 ditTerently. There is also a dilTcreivM? in their tlieoretic views as to the weight 

 of the molecule of sohilile starch and the natnrc^ of tlu; dextrins, hut we may 

 leave tliat aside. They imagine that the conversion of starch into maltose and 

 dextrin is to he reiiresented liy nine dillerent eipiations in the following manner. 



Ill 10(C'-H,„0,„| r n/J= C'-n^O„ ^1 9G'-H,„n,„(Erythro-dextrin a) 

 (2) J(mC'-H,„0,.,) + '2H,0=:2G'-H,,0„ + 8C'=H,„0,„( ., .. ,?) 



|3) 10 (C'-Ha.O,.,) + 3 }L0= 3C'-IL,0,| + 7 0"I-L„0,„ ( Achroo-dcxtrin. a) 

 14) 10(C'-H.„0,„) 1411,0= 4C'-IU0„ ^ <U:''IL„0,„( „ ., ,■') 



Tlie series is continued throiigh tlic intermediate! eciuatioris. 



(8) 10(C'-H,„0 J - - S H,0 = 8 C'-H,_,0„ + 2 C'-H,„0,„ (Aehroo-dextrin :) 



(9) 10(C'-H,„0„,)-f- 91-LO = 9("-H,/J,, -- C"-H„.0,„( ,, „ y,) 

 Of these the most stähle is No. ,S which represents the manner in which the 

 reiiotioit tukes place at and helow 63 C. They eonsidei' also that they have 

 definite) evidi'nee of the existence of equations -1,3. and 2, and indication.:! of 

 .") and Cy 



It will he seen that the weight of maltose tormed at low temperatures 

 is always greater llian at high temjieratures, a circumstunee which lias to l)e 

 carefully attended to in the projes.s of making beer, because it depends upon the 

 proportion of sugai' in the wort whctlier tlie brewed li(^uid will contain much or 

 little alcohol 



The above mentioned (diservers have been able (o (ditaiii definite chemical 

 eijualions hecaiise of the absence of any hydrating action of malt extract upon 

 maltose. As, however, it has been shown in Section 4 of this Blemoir that the 

 Rolulion of Uoji hydrates maltose, we cannot expect, even if that sugar is formed, 

 to obtjiiii results of ilic same sharpness as where the products first foiined are 

 unacted upon. 



Wo have, ihereforc. in tin" liisl place to as<'ertain whether maltose is one 

 of tlio pr.xhicls of tlie action of koji extract ujhiu starch paste, and that it is so, 

 will he shown by the following exiK;rimenls. 



To prove this an indirect method is resorted to, on accoiuit ol' tiie tliliiculty 

 of isolating small quantities of malto.se iti a [iure state from solutions containing 

 much dextrin. 'I'lie method adopted consists in determining i\u'. re(bi('irig 

 action of the solution upon oxide of cop|)cr, and from the .amoiird of cuprous 

 oxide ]irei-ipitated by a given v\ciglit of the starch pr<i(biet,s in solnlion 

 (uilci'.lated fioiii tlir SlK^cilic gravity of the liijuid I to lind the weigiit.; of maltose 



