A  Study  of  Starch  Grains. 
(  Am.  Jour.  Pharm. 
I      April.  1899. 
some  experiments  in  connection  with  Florence  Yaple  on  com- 
mercial starches,  as  well  as  the  starches  in  the  cells  of  the  tuber 
of  potato  and  fruits  of  wheat  and  corn,  with  the  following  reagents : 
(1)  Chloral  iodine      iodine  solution;  of  each  5  parts. 
(2)  Chlor-zinc-iodide  solution. 
(3)  Chromic  acid  solution  (15  per  cent.). 
(4)  Calcium  nitrate  solution  (30  per  cent.). 
($)  Chloral  solution  (saturated),  water  and  glycerin;  of  each  33 
parts.  To  this  solution  as  much  iodine  is  added  as  the  solution  will 
take  up. 
(6)  Salivar 
(7)  Silver  nitrate  (2  per  cent.). 
(8)  Sulphuric  acid  (C.  P.  acid  90  parts  and  water  10  parts). 
(9)  Taka  diastase  (saturated  solution). 
(10)  Sodium  acetate  solution  (50  per  cent). 
(n)  Potassium  hydrate  solution  (^  of  1  per  cent.). 
( 1 2)  Potassium  nitrate  solution  (saturated). 
(13)  Tannin  solution. 
(14)  Potassium  phosphate  solution  (saturated). 
(15)  Hydrochloric  acid  (5  per  cent.). 
The  numerous  drawings  which  we  present,  indicate  that  there  are 
characteristic  results  obtained  by  the  use  of  these  reagents.  I 
will  not  take  the  time,  however,  to  consider  the  details  of  the 
aforesaid  experiments,  as  they  will  be  incorporated  in  a  subsequent 
paper  to  be  presented  before  the  Cincinnati  Section  of  the  Ameri- 
can Chemical  Society. 
An  examination  of  the  commercial  starches  shows  that  there  are 
certain  amounts  of  impurities  associated  with  them  which  may  fur- 
ther serve  as  a  means  of  identification.  Meyer  has  shown  that 
potato  starch  contains  from  0-27  to  0-62  per  cent,  of  mineral  sub- 
stance ;  the  amount  of  water  is  generally  about  20  per  cent.;  and  that 
it  generally  contains  about  0  322  per  cent,  of  nitrogen  ;  there  is  also 
present  a  body  which  is  soluble  in  ether  and  which  gives  a  bad  odor 
on  heating  a  solution  with  hydrochloric  acid.  The  starch  may  be 
purified  by  washing  with  water  containing  ammonia  which  does  not 
alter  the  starch  grain  as  potassium  hydrate  does. 
Wheat  starch  of  commerce  reacts  acid  and  contains  lactic  acid, 
acetic  acid  and  protein  matters.  Rice  starch  gives  an  alkaline  reac- 
tion. 
