A  tit.  Ji  >nr.  Pharin. 
Feb.,  1893. 
Caffeine  and  Tlicinc. 
S3 
during  the  titration.  Assays  made  with  six  samples  of  ipecac  root 
(No.  5,  the  root  used  in  making  the  fluid  extracts;  No.  6,  aselected 
Carthagena-ipecac  from  Caesar  and  Lofetz)  gave  the  following 
results : 
i  23456 
Per  Cent. 
Emetine  by  weighing  the  residue,  .  .  3*032    3'078  3*148  3*028  2*620  2*700 
Emetine  by  titrating  the  residue,  .  .  2*794    2*743  2*844  2743  2'5^>5  2*438 
Difference  between  the  two,    ....  0*238    0*335  0*304  0*285  0*055  0*262 
From  these  results  a  pharmacopceial  requirement  of  2-5  per 
cent,  emetine  in  the  ipecac  root  would  not  be  too  exacting.  As  the 
objection  that  the  assay  determines  not  only  emetine  but  cholin 
may  be  raised  against  this  method,  the  alkaloidal  residue  from  50 
grams  of  the  root  was  dissolved  in  dilute  alcohol,  neutralized  with 
hydrochloric  acid,  evaporated  to  dryness  and  dissolved  in  a  little 
water;  this  solution,  which  should  contain  the  cholin  as  hydro- 
chloric, was  distilled  with  baryta  water,  but  the  distillate  was  found 
to  be  entirely  free  from  cholin. 
CAFFEINE  AND  THEINE  :  THEIR  IDENTITY  AND  THE 
REACTIONS  OF  CAFFEINE  WITH  AURIC  CHLORIDE.1 
By  Wyndham  R.  Dunstan  and  W.  F.  J.  Shepheard. 
From  the  Research  Laboratory  of  the  Pharmaceutical  Society. 
In  consequence  of  the  conclusions  of  Mayo  (Journ.  Physiol.,  7, 
458  ;  Therapeutic  Gazette,  1866,  587)  and,  more  recently,  of  Lauder 
Brunton  and  Cash  (Proc.  Roy.  Soc,  42,  283  ;  Journ.  Physiol.,  9,  1 12), 
that  the  physiological  action  of  theine  obtained  from  tea  differs 
in  certain  respects  from  that  of  caffeine  obtained  from  coffee,  the 
authors  have  searched  for  evidence  of  isomerism  in  these  bases,  the 
existence  of  which  is  not  put  beyond  doubt  by  the  chemical  com- 
parison of  them  which  has  hitherto  been  made. 
Having  extracted  theine  from  tea  and  caffeine  from  coffee  it 
is  shown  that  the  two  substances  exactly  resemble  each  other 
and  melt  at  precisely  the  same  temperature,  viz.,  234-5°  (corr.). 
From  each  base  the  crystalline  anro chloride  (C8H10N4O2,HCl,  Au 
C13,2H20)  was  prepared,  and  these  two  salts  both  melted  at  242-5° 
(corr.).    When  dried  at  100°  they  both  lost  the  equivalent  of  two 
1  The  substance  of  a  communication  made  to  the  Chemical  Society  011 
December  15*;  reprinted  from  Phar.  Jour,  and  Trans.,  Dec.  17,  1892,  p.  481. 
