'26 



nml dextrin, iissuming lliuse to be tho j(ni(liK-tH. If u-i other substnncü is formed, 

 the specific rotatory jiower of the solution i-aKniluttvl fioin tlie penvntnjteK ..f 

 inultosc and doxtrin pirsent will a^rve willi the sjiec-itie rotatory power «f tlie 

 hohition actually oh^ervt-d. If they ilo agree tliccohilion iiiiiBl contHin thHKxlien 

 assumed to be present. U'c-mso if others were then", tlie wptiific rotatory |)ower» 

 wonhl diiYor Iroiu one «iiotln-r. A detuiieil des.-riptioii of one ex|>«Timfiit will 

 render this more int<'lligihle. 



K.rjiitime>it ~. A koji 8olntion wn« prepare«! by digesting fora»hort time 

 2") grams of a freslily itrejuued sample of koji in alMHit 1<H1 c.c. of water. The 

 liipiid vvjvs then filtered, the residue di;,'esled with a tVesh «jniintify of water, and 

 the whole thrown uiwn the filter and «ashed until the filtriii«- amounted nmrly 

 to r>U<) e.c. Tiiu solution was then diluted exactly to 5<» e.e. at IS'C. The 

 filtnition occupi<,*d three or four hours even with the assistana- of n filter pump 

 on account of the plimy niilure of the insoluble matter. The »dntion ho miule 

 contained in 10<) c.c. 1.4G gram of solid matter calculated from the RfHrific 

 gmvity (using the divisor 3.8(5», I.OI-i.'i gmm glucone. and caune<l an optieal 

 rotation of 8 divi-ions in a 2r>0 m.m. ful.e. This gives a B|K»eiric rotatory |Kiwer 



8 ' 242 

 f"l^ = 2 ' 00146 = '''^-^ 



5 "rams of starch, iireviouslv ibied at lOO'^t,'.. were gelatiniiw«! with alwut 

 75 c.c. of water, the |>asle allowed to cool to 40^i;., then mixed with 25 c c. of 

 the koji solution, and left for 25 miinifes till it wasquite clear. It was then 

 rajiidly heated to boiling, cooled, and diluted to2.")0 c.c. 100 c.c. of ibis solution, 

 after filtration, contained 2 15 grams of solid matter, and I"»fi3 gn»in gbieotie, 

 determined by weighing the reduced cupiwis oxide after ignition. The oplicn) 

 rotation in a 20<.1 m m. fulie was 32.4 divisions. 



As tlie koji solution contained in 250 c.c. of the starcli pnxbicts wiu» 25 cc. 

 ( 1. (. one-tenth I we must ileduct the weight of s<iliil matter and glucose contained 

 in 10 c.c. of the koji extract from the weights abo\e found in 100 cc. of tho 

 liquid. The optical rotation must also lie diminished by one-tenth the amount 

 caused by the koji solution alone. We thus get: — 



Solids in TOO c.c. formed from starch ... 2.15 - 146 = 2.f)fM gnims. 



Sugar, calculate«! as glucose, <>3 .101= 521) 



Optical rotation 32.4— 0.8= 31.6 «livisions. 



31 6 0->42 

 Thns|«i. .•l-rvcd= ., . ,„,,^,4 = H«''-« 



The i>ercenti>'." ■ l" ^i 'h i I'mlit. d as ijlucofle is 26.31», and the multo«j corre- 



EDODdiuir is " - .■- i ■ . ^^>" and the dextrin, therefore, l«>0 — 43.28 



' ** U.6I ' 



= 56.72. If w( ' •' specific rotatory iK)w«jr which a mixture of maltose 



and dextrin in ti , , n- ought to have we fin<l it to U' 



[a], calculated = 216 ■ 0.567 -r 150 - 0.433 = 187''.4. 



