440  ' 
Chemical  Notes. 
Am.  Jour.  Pkarm. 
Sept.,  1890. 
Whether  sliding  tube  or  rack  and  pinion,  is  merely  a  matter  of 
convenience  and  dollars  and  cents. 
German  vs.  American  Microscopes. — With  45  per  cent,  duty  the 
American  instruments  are,  dollar  for  dollar,  superior  to  German 
ones  at  the  same  price ;  of  late  several  American  firms  have  been 
making  stands  according  to  the  squat  German  model  for  those  who 
prefer  short  stands. 
Book. — Next  to  a  living  teacher  comes  a  good  manual,  and  the 
writer  knows  of  none  better  or  more  instructive  handbook  of 
microscopical  technique  than  the  Technical  History  of  a  Slide,  by 
Dr.  Frank  L.  James,  St.  Louis,  Mo.  He  generally  gives  the  "  why  " 
and  "  wherefore  "  of  every  step. 
Patience. — Without  much  patience  and  a  corresponding  amount 
of  failures  few  will  become  expert  microscopists.  Through  failures 
we  learn ! 
CHEMICAL  NOTES. 
By  Henry  C.  C.  Maisch,  Ph.G.,  Ph.D. 
On  Cocaine. — A.  Einhorn  and  A.  Marquardt  (Ber.  d.  Deutsch. 
chem.  Gesell.,  1890,  468)  treated  ecgonine  with  potassium  hydrate 
and  obtained  an  isomeric  base  which  is  dextrogyre  while  ecgonine 
is  laevogyre.  On  treating  the  methyl  ether  of  this  base  with 
benzoyl-chloride  a  dextrorotary  alkaloid  isomeric  with  cocaine  was 
obtained.  The  alkaloid  which  C.  Liebermann  and  Giesel  noticed 
in  the  technical  synthesis  of  cocaine  and  which  they  named  methyl- 
cocai?ie  [Ber.,  1890,  508)  seems,  according  to  newer  investigations, 
to  be  identical  with  the  above  alkaloid  {Ber.,  1890,  926). 
The  first-named  author,  A.  Einhorn,  has  succeeded  in  going 
from  a  derivative  of  cocaine,  anhydro ecgonine  C5H7  (CH  =  CH— 
COOH)NCH3,  to  one  of  atropine,  tropidine  C5H.  (CH  =  CH2) 
NCH3  by  heating  anhydroecgonine  with  concentrated  hydrochloric 
acid  to  2800  C  for  8  hours.  Among  others  there  is  one  base 
formed  which  yields  a  gold  salt,  melting  at  2120  C.  On  decompos- 
ing this  double  salt  or  better  the  picrate,  abase  C8H13N  is  obtained> 
^.vhich  proved  to  be  tropidine.    (Ber.,  1890,  1338.) 
On  Cinchonamine. — Arnaud  (Ann.  Chim.  Phys.  (6)  ip  (1890)  93) 
among  other  things,  in  reviewing  his  work  done  on  this  new  cin- 
chona alkaloid,  gives  the  following  method  for  estimating  nitric  acid 
based  on  the  slight  solubility  of  cinchonamine  nitrate.    The  solu- 
