Am"ja0iy!i889arm"}  Gleaning 's  from  the  German  Journals.  355 
Starch  determinations. — Asboth's  method  of  precipitating  gelatinized 
starch  by  barium  hydrate  in  presence  of  alcohol  has  been  repeatedly 
criticized  as  to  its  value  in  the  examinations  of  cereals,  inasmuch  as 
Lintner's  method  of  converting  the  starch  into  glucose  by  action  of 
diastase  and  dilute  acid  always  gave  results  which  were  6-8  per  cent, 
lower.  Asboth,  Chemiker  Ztg.,  1889,  591  and  611,  has  studied  the 
causes  of  the  differences  and  finds  them  due  to  the  presence  of  fats  or 
oils  which,  by  containing  free  acids  or  easily  decomposable  glycerides, 
combine  with  the  barium  hydrate  and  thus  increase  the  results  for 
starch.  This  source  of  error  is  now  removed  by  extracting  the  sub- 
stance first  with  ether  to  remove  fats,  exposing  the  extracted  substance 
to  the  air  to  remove  the  ether  and  determining  in  one  portion  the 
moisture,  in  another  portion  the  starch  as  follows  :  About  1*5  gm.  are 
gelatinized  in  a  flask  with  100  cc.  wTater,  after  cooling  to  the  ordinary 
temperature,  50  cc.  barium  hydrate  solution  added,  thoroughly  mixed 
by  agitation,  and  then  diluted  with'  alcohol  of  45  per  cent,  to  make 
250  cc.  After  the  precipitate  has  completely  subsided  50  cc.  of  the 
clear  liquid  representing  10  cc.  Ba(OH)2  are  removed  with  a  pipette  and 
in  this  the  Ba(OH)2  determined  by  titration  with  ^  n  hydrochloric 
acid,  using  phenolphthalein  as  the  indicator.  10  cc.  of  Ba(OH)2  so- 
lution must  also  be  titrated  and,  the  difference,  in  cc.  ^  n  HC1,  be- 
tween the  two  titrations  multiplied  by  0.162  will  give  the  amount  of 
starch  in  the  weight  taken ;  this  figure  must  be  re-calculated  for  the 
original  fat-containing  cereal. 
An  insecticide  of  especial  value  against  the  Phylloxera  is  made  by 
saponifying  any  vegetable  oil  with  sulphuric  acid,  incorporating  car- 
bon disulphide  and  exactly  neutralizing  with  an  alkali ;  this  prepara- 
tion is  as  efficacious  as  pure  carbon  disulphide,  but  is  not  volatile  and 
is  miscible  with  water.  In  contact  with  water  or  moist  soil,  slow  de-' 
composition  takes  place  with  evolution  of  S02  and  mercaptans,  which 
latter  increase  the  effectiveness. — Kuhl,  Apotheker  Ztg. ,18&9,  506. 
Mandragorine  is  the  name  of  the  alkaloid  which  was  found  in  the 
roots  of  Mandrogora  autumnalis  and  M.  vernalis  by  extracting  with 
alcohol,  recovering  the  alcohol  by  distillation,  taking  up  the  residue 
with  water  acidulated  with  sulphuric  acid,  rendering  the  solution 
alkaline  with  potassium  carbonate,  agitating  with  ether  and  evaporat- 
ing this  solution.  The  alkaloid  melts  at  77—79°,  and  has  the  formula 
C17H23N03 ;  the  sulphate  forms  lustrous,  deliquescent  scales,  the 
solution  of  which  introduced  into  the  eye  dilates  the  pupil.  Although 
