5<5o 
Caffeine  in  Tea  and  Coffee. 
(  Am.  Jour.  Pharm. 
(     August,  1921. 
bodies.  Diphtheria  antitoxin,  which  has  been  studied  longest  in  an 
intensive  manner,  has  served  as  the  prototype  of  this  class  of  sub- 
stances. There  has  been  much  evidence  to  indicate  its  close  relation- 
ship or  association  with  certain  proteins,  notably  the  globulins  of 
the  blood.  It  is  not  analogous  to  enzymes,  if  one  may  judge  from 
the  failure  of  antitoxin  to  be  adsorbed  by  or  removed  from  solution 
with  a  variety  of  indifferent  precipitates.  The  large  size  or  colloid 
character  of  the  antibody  molecule  is  shown  by  its  comparative  non- 
diffusibility.  Recent  studies  by  Huntoon,  Masucci  and  Hannum  have 
helped  to  narrow  the  field  of  investigation  somewhat  by  indicating 
more  clearly  than  heretofore  that  antibodies  do  not  belong  to  that 
group  of  proteins  usually  classed  as  serum  proteins.  They  showed, 
as  others  have  previously  indicated,  that  antibodies  resist  tryptic  di- 
gestion— a  fact  which  makes  them  unlike  ordinary  proteins.  Anti- 
bodies, furthermore,  do  not  manifest  those  biochemical  reactions  and 
transformations  which  are  at  present  ascribed  to  the  ill-defined  eu- 
globulin  and  pseudoglobulin  fractions  of  the  blood.  Being  insoluble 
in  ether,  they  cannot  be  classed  as  lipoids  or  fats.  By  knowing  more 
precisely  what  antibodies  are  not,  we  may  hope  to  succeed  better  in 
the  coming  years  in  learning  more  adequately  what  they  really  are.; 
A  NEW  METHOD  FOR  THE  DETERMINATION  OF  CAF- 
FEINE IN  TEA  AND  COFFEE.* 
No  samples  of  tea  were  examined  during  the  past  year  for  in- 
spection purposes,  but  methods  for  the  determination  of  caffeine 
were  further  studied  and  the  results  included  in  the  report  of  the 
writer  as  Referee  on  tea  to  the  Association  of  Official  Agricultural 
Chemists  at  their  annual  meeting  in  November,  1920. 
The  Power  and  Chestnut  method1  was  studied  and  recommended 
to  the  Association  as  an  official  method.  The  Stahlschmit  method2 
which  is  now  tentative  was  further  modified3  so  that  caffeine  resi- 
dues of  a  high  degree  of  purity  can  be  obtained.   A  new  proceedure 
*From  the  Connecticut  Agricultural  Experiment  Station  Bulletin  No. 
227,  Feb.,  1 92 1. 
1Jour  Am.  Chem.  Soc,  41,  1300. 
2  Jour.  A.  O.  A.  C.  2,  3,  332. 
3  By  C.  E.  Shepard  and  the  writer. 
