194 
Reviews. 
Am.  Jour.  Pharm. 
April,  1899. 
Prolliu's  short  method  for  the  assay  of  cinchona  bark  ;"  on  page  30,  in  com- 
menting particularly  upon  Keller's  method  there  is  stated  that  all  processes  in 
which  ether  or  even  compound  solvents  are  used,  and  in  which  an  aliquot  por- 
tion of  the  solvent  is  taken  to  complete  the  assay,  "it  may  be  expected  that 
the  result  of  the  assay  will  be  high."  The  distinctively  characteristic  feature 
of  Keller's  method  in  the  assay  of  crude  drugs  is  the  addition  of  water  to  cause 
the  lumpiug  together  of  the  powder  drug  thus  enabling  the  solvent  to  be 
poured  off  clear,  and  this  feature  has  been  adopted  in  the  present  volume.  This 
addition  of  water  was  undoubtedly  the  main  factor,  causing  low  results  in  some 
assays  of  belladonna  leaves  recently  made  by  the  writer  (Am.  Jour.  Pharm. 
1899,  105). 
In  processes  in  which  an  aliquot  portion  of  the  solvent  is  used,  the  quantity 
of  drug  represented  by  this  portion  should  always  be  stated  ;  this  has  been 
omitted  in  some  cases,  and  is  somewhat  puzzling,  as  one  then  does  not  know 
whether  the  particular  process  makes  allowance  for  extractive. 
In  giving  the  percentages  of  active  constituents  in  the  various  drugs,  it  would 
be  of  great  value  to  state  by  what  assay  processes  these  results  were  obtained  ; 
this  could  only  be  exceeded  in  value  by  incorporating  comparative  assays  of 
the  same  drug  by  the  various  methods. 
An  additional  word  or  two  occasionally  would  be  of  considerable  help  in 
understanding  a  process;  this  is  particularly  the  case  when  a  drug  is  to  be 
treated  with  a  solvent  which  has  for  its  object  the  removing  of  some  interfering 
substance  before  proceeding  with  the  assay  proper.  For  example,  Hager's 
method  of  estimating  aloes  in  mixtures,  page  100,  would  be  better  understood 
if  the  statement  were  made  that  the  first  extraction  with  the  absolute  alcohol, 
chloroform  and  benzol  mixture  removes  other  resinous  substances  (jalap  resin 
in  particular),  and  that  the  portion  insoluble  in  this  mixed  solvent  is  to  be  ex- 
tracted with  alcohol. 
The  exact  details  of  official  assay  processes  are  only  given  under  cinchona; 
under  opium  the  reader  is  referred  to  the  original  publication  by  Dr.  Squibb 
in  the  ephemeris,  while  under  nux  vomica  no  mention  of  any  kind  is  made  of 
the  official  process;  it  seems  to  the  writer  that  these  processes  should  be  given 
prominence  in  the  book,  particularly  as  the  assay  processes  of  the  U.S. P.,  1880, 
for  cinchona  and  opium  have  been  accorded  space. 
Under  opium,  page  206,  in  referring  to  the  correction  for  impurities  in  the 
crude  morphine,  the  lime  water  and  ash  methods  are  mentioned;  in  the  latter 
the  statement  is  misleading,  the  factor  usually  employed  for  calculating  ash  to 
calcium  meconate  (?),  the  supposed  morphine  impurity,  being  omitted. 
The  method  of  E.  Dieterich  adopted  by  the  German  Pharmacopoeia  is  his 
original  process;  no  mention  is  made  of  the  improvement  of  the  process  by 
substituting  acetic  ether  for  ether. 
On  page  213  (401)  the  quantity  of  tincture  of  opium  used,  160  c.c,  should 
be  150  c.c.  to  agree  with  the  process  to  which  reference  is  made. 
On  page  214  (402)  in  the  processes  for  assay  of  extract  of  opium,  the  quan- 
tities used  do  not  accord  with  those  in  the  cross-references;  in  these  cases  par- 
ticularly the  quantity  of  drug  represented  by  the  aliquot  portion  taken  should 
be  stated. 
The  following  typographical  errors  were  noticed  in  a  careful  perusal  of  the 
work,  and  should  be  added  to  the  published  list: 
