AmNJo0vU,r'i?79ariD' }  8tudy  °f  Organic  Chemistry  by  Pharmacists.  535 
acid,  a  coal-tar  product,  or  from  hippuric  acid,  which  is  found  abun- 
dantly in  the  urine  of  herbivorous  animals.  For  the  sake  of  those  who 
have  prejudices  we  may  say  that  the  officinal  benzoic  acid  is  prepared 
solely  by  the  first  process. 
Indigo-blue  has  been  prepared  artificially  by  Baeyer.  As  yet  the 
process  is  hardly  simple  enough  to  be  made  a  commercial  one,  but  there 
is  no  doubt  that  it  will  ultimately  be  made  so. 
In  the  group  of  alkaloids  not  so  much  has  been  done  as  yet,  but  as 
the  incentives  are  very  great  we  have  every  reason  to  await  greater 
results  in  the  future. 
Schiff  prepared,  in  1870,  paraconine,  an  alkaloid,  isomeric  with  true 
conine  but  differing  from  it  in  properties. 
Caffeine  is  shown  to  be  the  methyl  derivation  of  theobromine  and 
can  be  prepared  from  it. 
Atropia  has  been  made  artificially  by  Ladenburg  by  combining 
tropine  and  tropic  acid,  the  two  decomposition  products  of  the  original 
alkaloids.  He  is  now  engaged  in  the  effort  to  build  up  synthetically 
these  two  simpler  compounds,  and  with  all  hopes  of  success.  The  arti- 
ficial atropia  has  the  same  physiological  action  upon  the  eye  as  that 
possessed  by  the  natural  alkaloid,  and  appears  to  be  identical  with  it  in 
every  respect. 
Chinolin,  a  product  of  the  treatment  of  the  quinia  alkaloids  with 
caustic  potash,  has  been  recently  prepared  synthetically  by  both 
Koenigs  and  Baeyer.  The  synthesis  of  cinchonia  is  now  being 
attempted  by  several  chemists  with  strong  prospects  of  success. 
The  most  recent  synthesis  effected,  and  one  of  the  most  interesting 
and  suggestive,  is  that  just  effected  by  Michael  in  Wurtz's  laboratory. 
He  has  built  up  helicin,  the  oxydation  product  of  salicin,  from  a  deri- 
vative of  glucose,  called  aceto  chlorhydrose  and  salicylic  acid.  As 
helicin  is  reducible  by  nascent  hydrogen  to  salicin,  this  is  equivalent 
to  a  synthesis  of  the  glucoside  itself.  Moreover,  the  method  is  a  gen- 
eral one,  and  Michael  promises  to  attempt  at  once  the  synthesis  of  other 
and  more  important  glucosides. 
It  will  be  seen  from  this  imperfect  list  that  much  has  been  accom- 
plished in  the  past ;  but  what  has  been  done  is  only  an  earnest  of  what 
we  may  expect  in  the  future  from  the  rapidly  increasing  attention  now 
directed  to  this  subject.  If  in  the  ten  years,  from  the  discovery  of 
artificial  alizarin,  by  Graebe  and  Liebermann,  in  1868,  the  production 
