302       Recent  Literature  Relating  to  Pharmacy,  {Amj"inUe?i902arm' 
Aconitine,  brucine,  cocaine,  lobeline,  nicotine  and  pilocarpine,  in 
weak  solution,  are  only  sparingly  precipitated  by  tea;  coffee  does 
not  affect  them  even  when  they  are  in  concentrated  solutions. 
Apomorphine,  the  cinchona  alkaloids,  hydrastinine,  strychnine, 
and  veratrine  in  dilute  solutions  are  precipitated  efficiently  by  either 
coffee  or  tea,  the  latter  being  generally  more  efficient,  except  per- 
haps for  veratrine  and  quinine. 
The  precipitation  is  incomplete  with  all  alkaloids  except  ape- 
morphine.  However,  the  quantity  of  unprecipitable  alkaloid  is  quite 
small  in  those  which  are  said  to  precipitate  from  "  dilute  solution," 
since  most  of  the  alkaloid  is  removed  from  I  :  2000  solutions. 
The  precipitates  are  somewhat  soluble  in  dilute  HC1,  very  readily 
soluble  in  dilute  alcohol.  The  administration  of  the  latter  must 
therefore  be  avoided  if  these  beverages  (or  tannin)  are  used  as 
chemical  antidotes  in  alkaloidal  poisoning.  Since  the  precipitates 
are  not  quite  insoluble  in  water,  as  little  liquid  as  possible  should  be 
given.  The  quantities  of  the  decoctions  should  not  be  less  than 
3  c.c.  of  a  well-boiled  10  per  cent,  decoction  for  each  milligram  of 
alkaloid. 
II.  — Metallic  Salts1. — Tea  is  also  the  more  efficient  precipitant  of 
metals,  but  the  difference  is  not  nearly  so  striking  as  with  alkaloids. 
Both  beverages  are  inefficient  against  arsenious  acid  or  tartar  emetic. 
They  precipitate  to  a  large  extent,  but  not  quite  completely,  the 
salts  of  cobalt,  copper,  nickel,  uranium  and  zinc,  and  would  be  use- 
ful antidotes  against  the  toxic  members  of  this  list.  They  precipi- 
tate practically  completely  the  salts  of  aluminum,  lead  and  silver. 
Mercury  is  partly  precipitated  by  tea,  but  not  by  coffee,  so  that  the 
former  would  be  an  antidote,  the  latter  not. 
III.  — Proteids  (Eggwkite,  Albumose  and  Gelatine). — These  differen- 
tiate very  sharply  between  the  two  tannins  ;  whereas  tea  pro- 
duces  large  precipitates,  coffee  leaves  them  unaffected,  or  renders 
them  slightly  turbid  at  most.  This  serves  to  explain  the  less  astrin- 
gent taste  of  coffee  and  its  less  deleterious  effect  upon  digestion. 
The  reactions  of  tea  bear  a  very  close  resemblance  to  those  of 
gallotannic  and  quercotannic  acid.    The  precipitant  effects  of  caffeo- 
1  The  salts  used  were  :  Arsenious  acid,  tartar  emetic,  cobalt  chloride,  cupric 
sulphate,  nickel  sulphate,  uranium  acetate,  zinc  sulphate,  ferric  chloride,  lead 
nitrate,  silver  nitrate,  aluminum  chloride  and  mercuric  chloride. 
