522  British  Pharmaceutical  Conference.  {Am'oSE!fi^ann 
ally  used  in  the  preparation  of  terebene  and  taking  18°  6"  as  the  standard  of 
rotation  of  this  variety  of  turpentine,  Mr.  Hodgkin  based  his  calculation  as  to 
the  amount  of  unaltered  turpentine  in  a  sample  upon  the  extent  of  its  rotatory 
power,  an  essential  character  of  pure  terebene  being,  as  is  known,  its  absence 
of  any  effect  upon  a  beam  of  polarized  light.  ZSTine  samples,  two  of  which 
were  foreign,  gave  results  indicating  the  presence  of  unaltered  turpentine,  cal- 
culated upon  this  assumption,,  varying  between  3.2  and  61  per  cent,  of  unaltered 
material.  One  of  the  samples  giving  the  best  indications  according  to  this  test 
was  described  as  having  u  a  slight  smell  of  turpentine,'''  whilst  another  sample 
said  to  have  a  u  pleasant  "  odor  gave  indications  construed  to  show  the  pres- 
ence of  32.9  per  cent,  of  unaltered  turpentine.  It  was  objected  to  this  test  that 
American  turpentine  is  not  constant  in  its  rotatory  power,  but  Professor  Arm- 
strong remarked  that  the  variety  showing  the  greatest  deviation  from  the  stand- 
ard comes  from  Savannah  and  is  relatively  small  in  quantity,  so  that,  on  the 
whole.  American  turpentine  is  fairly  uniform  in  this  respect.  Some  little 
amusement  was  caused  when,  upon  Mr.  Mo>s  stating  that  he  had  based  his  pro- 
cess for  the  manufacture  of  terebene  upon  the  published  researches  of  Messrs. 
Armstrong  and  Tildem  Professor  Tilden  declared  that  the  outcome  of  their  re- 
search was  to  prove  that  no  definite  body  corresponding  to  that  originally 
described  as  terebene  existed  ;  but  the  apparent  contradiction  will  be  under- 
stood in  the  light  of  a  remark  by  Mr.  Allen  that  the  name  was  applicable  even 
if  it  were  only  to  a  mixture  of  hydrocarbons  obtained  by  the  molecular  modifica- 
tion of  turpentine  until  it  no  longer  was  capable  of  exercising  a  rotatory  power 
on  polarized  light. 
Emetine. — In  some  notes  on  the  estimation  of  emetine,  Mr.  H.  W.  Jones  spoke 
favorably  of  Fliickiger's  method  for  assaying  ipecacuanha,  which  consists  in  ex- 
hausting the  finely  powdered  root  with  chloroform  containing  a  trace  of  am- 
monia (see  Ant.  Thar.  Joum.  1886.  p.  127). and  weighing  or  titrating  the  residue 
after  evaporation.  The  author  stated  that  the  alkaloid  is  removed  in  this  way  in 
an  unaltered  condition, but  he  agreed  with  Mr.  Alcock  (Phar.  Jo  t/r.,xvi.)..  that  the 
chloroformic  residue  is  only  imperfectly  soluble  in  acidulated  water,  and  said 
he  therefore  preferred  to  treat  it  with  water  and  dilute  sulphuric  acid,  filter 
through  cotton  wool  and  recover  the  alkaloid  with  chloroform  and  ammonia. 
In  respect  to  the  titration  with  Mayer's  reagent,,  by  experiments  with  pure 
emetine  Mr.  Jones  has  found  that  in  faintly  acid  solutions  the  most  exact  indi- 
cations are  given  when  the  dilution  is  in  the  proportion  of  about  1  in  530  ;  but 
as  the  error  appears  to  increase  regularly  with  the  degree  of  concentration,  he 
has  constructed  a  table  of  factors  for  correction  of  results.  Mr.  Jones  also  cor- 
roborates the  opinions  which  have  been  expressed  that  the  amount  of  emetine 
in  good  ipecacuanha  does  not  greatly  exceed  1  per  cent.,  and  attributes  higher 
results  that  have  been  recorded  to  the  action  upon  the  reagent  of  substances 
other  than  emetine  that  have  been  taken  up  by  the  solvent  employed.  Other 
experiments  referred  to.  went  to  show  that  emetine  undergoes  alteration  in 
treatment  with  lime,  or  even  when  subjected  to  heat  alone  on  a  water  bath, 
increasing  slightly  in  weight.,  and  then  giving  in  acidulated  water  highly  col- 
ored solutions. 
Vinurn  vpecacnw.nl iz. — A  paper,  by  Mr.  J.  C.  Shenstone,.  gave  the  results  of 
some  experiments  made  to  compare  the  behavior  of  samples  made  with  natu- 
