626  Chemical  Notes  on  Tea.  {Am,Dec.%^arm' 
table  mixtures  and  for  toning  down  concoctions  intolerable  of  exhibi- 
tion from  their  bitterness,  it  will  doubtless  prove  serviceable,  but  at 
present  the  scope  of  its  application  must  be  in  general  limited  to  pro- 
prietary articles  and  to  medicines  prescribed  by  the  physician.  To 
employ  it  as  an  adjuvant  to  official  remedies  would  assuredly  not  be 
justifiable. 
I  can  conceive  that  "the  manner  in  which  it  lingers  on  the  palate  " 
may  prove  an  objection  to  its  use  in  cases  where  the  growing  tendency 
has  been  to  exhibit  a  combination  of  drugs  or  their  preparations  in  a 
tasteless  form. — Phar.  Jour,  and  Trans.,  November  5,  1887,  p.  377. 
CHEMICAL  NOTES  OX  TEA. 
By  Dr.  B.  H.  Paul  and  A.  J.  Cownley. 
So  far  as  the  chemistry  of  tea  has  been  studied  its  most  important 
constituents  appear  to  be  an  essential  oil  to  which  the  aroma  is  due, 
theine,  legumin,  and  an  astringent  substance  analogous  to  tannin. 
With  the  exception  of  theine,  however,  little  is  known  of  the  chemi- 
cal characters  and  relations  of  these  constituents,  or  of  the  mode  in 
which  the  quality  of  tea  is.  influenced  by  them.  For  instance,  what 
is  commonly  spoken  of  as  the  "  strength  "  of  tea  is  a  tolerably  vague 
quality  in  itself,  and  no  relation  has  yet  been  ascertained  to  exist  be- 
tween it  and  the  amount  of  any  particular  constituent.  Considering 
the  physiological  properties  of  theine  it  might  be  supposed  that  the 
"strength"  of  tea  depends  to  a  considerable  extent  upon  the  amount 
of  this  substance,  and  some  probability  is  given  to  that  opinion  by  the 
great  variation  in  the  published  statements  as  to  the  proportions  that 
have  been  obtained  from  different  kinds  of  tea.  According  to  the 
earlier  determinations  by  Mulder,  Chinese  and  Java  tea  were  repre- 
sented to  contain  less  than  one  per  cent,  of  theine.  Subsequently, 
Stenhouse  found  from  one  to  two  per  cent,  in  a  number  of  samples 
examined  by  him,  while  Peligot  obtained  from  2" 5  to  4,  and  in  one 
case  as  much  as  5 '84  per  cent,  of  theine.  On  examining  the  methods 
by  which  these  results  were  obtained  they  all  appear  to  be  open  to 
suspicion  of  inadequacy  to  meet,  on  the  one  hand,  the  difficulty  of  ob- 
taining theine  in  a  sufficiently  pure  condition,  and  on  the  other  hand, 
that  of  extracting  the  whole  of  it  in  such  a  condition. 
The  method  of  sublimation  by  which  Stenhouse1  sought  to  deter- 
1  Phil.  Mag.,  xxiii.  (1843),  427. 
