138 
A  New  Local  A  naesthetic. 
/Am.  Jour.  Pharcn 
X      March,  1886. 
Dr.  Hesse  considers  that  cupreine  being  a  diamine  base,  is  therefore 
biacid,  and  that  it  is  also  in  virtue  of  its  phenol  nature  monobasic. 
Hence  it  can  combine  with  two  molecules  of  a  monobasic  acid,  and 
also  with  one  atom  of  a  metal,  such  as  K  or  Na.  When  either  of  the 
latter  compounds  is  brought  together  with  an  equivalent  quantity  of 
quinine  hydrochlorate  a  precipitate  is  formed  that  consists  essentially 
of  homoquinins. 
C19H21NaN202 + C20H24N2O2,HCl=NaCl + C20H24N2O2,C19H22N2O2. 
Dr.  Hesse  considers  that  this  simple  mode  of  forming  homoquinine 
proves  that  the  substance  is  only  a  compound  of  quinine  and  cupreine 
in  equal  molecular  proportions,  and  he  refers  to  his  analytical  results 
as  to  the  amount  of  quinine  in  homoquinine  as  being  in  harmony  with 
this  view. 
Lastly,  the  hydration  of  crystallized  homoquinine  has  been  rede- 
termined by  Dr.  Hesse,  and  he  finds  it  amounts  to  10*38  per  cent,  as 
against  10*19  calculated  in  accordance  with  the  formula — 
C20H24N2O2,C19H22N2O2H-4H2O. 
- — Pharm.  Jour,  and  Trans.,  January  23d,  1886,  pp.  622-625. 
A  NEW  LOCAL  ANAESTHETIC. 
At  a  recent  meeting  of  the  Medical  Society  of  Berlin,  Dr.  Lewin 
presented  a  most  interesting  series  of  observations  upon  the  physio- 
logical effects  of  a  resinous  extract  obtained  from  the  root  of  Piper 
methysticum,  which  is  soluble  in  alcohol,  possesses  a  somewhat  aro- 
matic taste,  and  leaves  upon  the  tongue  a  sensation  of  pricking  and 
burning,  soon  lost  in  the  supervening  local  insensibility.  When  the 
extract,  even  in  very  small  amount,  is  instilled  into  the  eye  of  an 
animal,  a  slight  local  irritation  is  evidenced  by  repeated  blinking, 
which  soon  yields  to  a  marked,  enduring,  and  complete  insensibility 
of  the  conjunctiva  and  cornea.  In  guinea-pigs  Lewin  has  seen  this 
insensibility  continue  for  more  than  an  hour,  normal  sensation  grad- 
ually returning.  The  iris  retains  throughout  its  reflex  re  sponsiveness 
to  optic  stimuli.  No  anatomical  lesions  of  the  cornea  or  conjunctiva 
were  observed  as  the  result  of  its  application. 
When  the  solution  of  the  extract  is  injected  hypodermically,  the 
tissues  with  which  it  comes  in  contact  completely  cease  to  respond  to 
the  application  of  thermic,  electric,  and  chemical  stimuli — a  transitory 
condition  which  is  followed  by  no  symptoms  of  inflammation. 
