372  Chemistry  of  British  Pharmacopoeia,  {Kmi'^'\^m' 
Methyl  Sulphonal  is  the  newly-coined  name  for  trional  (diethyl- 
sulphone-methyl-ethyl-methane),  but  why  it  is  called  methyl  sul- 
phonal,  when  it  differs  from  that  substance  by  an  extra  ethyl  group, 
is  a  mystery. 
Pelleterine  T annate  is  simply  defined  as  "  a  mixture  of  the  tan- 
nates  of  the  alkaloids  obtained  from  the  bark  of  the  root  and  stem  of 
Punica  granatum"  without  attempting  to  specify  the  alkaloids  by 
name,  as  is  done  in  the  U.  S.  P.  VIII. 
Phenolplvthalein,  of  course,  has  recognition,  owing  to  the  phe- 
nomenal increase  in  its  use  in  medicine  during  recent  years. 
Resorcin,  strange  to  say,  although  recognized  in  most  other 
pharmacopoeias  for  several  decades,  is  officially  described  for  the 
first  time. 
The  title  of  Sodii  Arsenas  has  been  corrected  to  Sodii  Arsenas 
Anhydrosus,  and  is  required  to  contain  not  less  than  98  per  cent, 
of  anhydrous  sodium  arsenate. 
Sodii  et  Potassii  Tartras  is  now  the  official  title  of  the  former 
soda  tartarata,  and  is  required  to  be  of  98  per  cent,  purity. 
In  Sodii  Phosphas  Acidns,  or  acid  sodium  phosphate,  we  have 
probably  the  first  official  recognition  that  has  ever  been  accorded 
to  sodium  dihydrogen  phosphate,  NaH2P04,  sometimes  known  as 
sodium  biphosphate.  It  is  required  to  contain  not  less  than  70  per 
cent,  of  the  anhydrous  salt,  and  is  assayed  by  titration  with  standard 
alkali. 
Strontium  Bromide  is  recognized  for  the  first  time,  although 
other  pharmacopoeias  have  long  included  it  among  the  official  sub- 
stances. It  is  required  to  contain  not  less  than  97  per  cent,  of 
SrBr2,6H20. 
Theobromine  and  Sodium  Salicylate  is  another  substance  recog- 
nized in  Great  Britain  for  the  first  time,  although  previously  given 
official  recognition  in  continental  Europe. 
Zinc  Oleostearate  is  the  official  title  of  the  product  made  by 
double  decomposition  and  precipitation  between  a  solution  of  zinc 
sulphate  and  a  solution  of  a  mixture  of  hard  soap  and  curd  soap. 
It  is  described  as  a  "nearly  inodorous,  yellowish-white,  or  grayish- 
white  powder,"  and  corresponds  closely  to  our  own  official  zinc  stear- 
ate,  misnamed  because  usually  made  in  the  same  manner.  The  curd 
soap  and  hard  soap  of  the  above  formula  are  respectively  animal 
fat  and  vegetable  fat  soaps  with  soda. 
