Am  Jour.  Pharm. 
July,  1889. 
Pharmaceutical  Assaying. 
339 
washing  with  strong  alcohol.  Cochineal  and  caramel  are  insoluble  in 
stronger  ether,  cudbear  is  slightly  soluble,  and  santal-red  is  easily 
soluble.    Caramel  is  insoluble  in  strong  alcohol. 
The  colors  can  be  further  tested  with  diluted  sulphuric  acid  ;  cochi- 
neal turns  yellow,  cudbear  and  santalum  do  not  turn,  or  only  very 
gradually.  Caramel  is  not  affected,  but  it  is  otherwise  easily  dis- 
tinguished. 
Any  color  fairly  above  that  of  the  regular  light-brown  of  the 
standard  ought  to  condemn  an  article,  so  that  the  special  examination 
for  colors  might  be  omitted. 
6.  Amount  of  Alcohol. — Dilute  50  cc.  with  100  cc.  water,  add  3 
gru.  recently-ignited  kaolin,  filter  in  closed  funnel  (to  rid  of  oil  anise, 
etc.,  etc.),  distil  off  50  cc.  and  determine  as  usual. 
N.  B. — The  distillate  may  still  contain  a  little  camphor,  etc.,  but 
not  enough  to  seriously  affect  the  sp.  gr.  of  it  (Drescher). 
Rhubarb. — Of  the  structural  and  general  physical  characters  of  the 
whole  root  it  is  needless  here  to  "  waste  eloquence,"  while  the  "  text 
books "  are  so  elaborate  in  their  description  of  this  drug ;  but  the 
"  powdered  "  root  merits  special  attention  here. 
1.  The  physical  properties  ought,  of  course,  be  noted,  as  compared 
with  a  sample  of  undoubted  quality — best  self-prepared. 
2.  Amount  of  Extract — (prepared  with  45  per  cent,  weight  alcohol) 
ought  to  be  about  47  per  cent.  (Hager) ;  35-58  per  cent.  (Drescher), 
minimum  and  maximum. 
3.  Ash. — 12-14  per  cent.  (Drescher) ;  sometimes  claimed  to  be 
much  more  (e.  g.,  43  per  cent.  (?)  Nat'l  Disp.1). 
4.  Chrysophanic  acid. — To  be  not  less  than  3  per  cent.  (Hager)  ; 
2'5  per  cent.  (Drescher). 
5.  Foreign  coloring  matters. — These  are  easily  detected,  according  to 
their  nature  (aniline,  coal-tar  derivatives,  curcuma,  etc.) ;  thus :  ani- 
lines (or  other  coal-tar  derivatives)  may  be  shaken  out  with  benzol, 
or  other  solvents,  etc.  Curcuma  is  certainly  discovered  by  the  methods 
proposed  by  Maisch  and  Howie  [see  U.  8.  Disp.,  NaflDisp.,  Uager's 
Phar.  Praxis,  etc.]. 
6.  Chrysophanic  acid. — 10  grammes  coarsely  powdered  rhubarb  is 
1  43.27  per  cent.  See  Pharmacographia,  1st  Edition,  page  449  ;  2d  Edit.,  p. 
500.— Ash  3  to  43  per  cent.;  Marme,  Pharmacognosie,18S6,  p.  86.— Aschengehalt 
steigt  bis  40  pro  cent.,  Moeller,  Pharmakognosie,  1889,  p.  319. — Editor  Am.  Joue. 
Phae. 
