6io 
Current  Literature. 
f  Am.  Jour.  Pharm. 
December,  191 7. 
as  diffusion  is  complete,  very  numerous  characteristic  bipyramidal 
crystals,  frequently  truncated,  somewhat  resembling  the  crystals  of 
magnesium  ammonio-phosphate  found  in  urine,  will  appear  in  the 
field.  Under  like  conditions,  rubidium  and  caesium  afford  typical 
micro-crystalline  precipitates.  Lithium,  ammonium,  and  thallium 
give  no  such  reaction.  Besides  cocaine,  the  soluble  salts  of  tropo- 
cocaine,  berberine,  narceine,  cotarnine,  and  papaverine  all  give  dis- 
tinctive crystals  with  sodium  perchlorate.  A  concentration  of  I  :  20, 
or  even  1  : 10,  may  be  necessary  for  their  rapid  formation.  Some- 
times, as  with  papaverine,  the  precipitate  at  first  has  an  emulsion- 
like aspect;  but  on  re-solution,  by  warming,  followed  by  friction,  a 
turbidity  is  obtained  which  speedily  affords  tufts  of  crystals.  Mor- 
phine, in  1  : 100  solution,  or  stronger,  at  once  forms  spontaneous 
groups  of  long  needles  radiating  from  a  common  center.  The  per- 
chlorates  of  its  alkyl  derivatives,  and  especially  codeine,  give  per- 
chlorates  which  are  much  more  soluble.  Brucine,  and  especially 
strychnine,  give  characteristic  micro-crystalline  perchlorates  with 
great  facility.  A  1 :  100  solution  of  brucine  salts,  or  the  alkaloid  in 
free  acetic  acid  when  treated  with  sodium  perchlorate  on  a  slide, 
gives  crystals  spontaneously ;  and  when  rubbed  with  a  fine  stirrer 
until  turbidity  appears,  a  characteristic  micro-crystalline  reaction 
may  be  easily  obtained  with  a  dilution  of  1  : 200,  and  on  rubbing  with 
a  1  :  1000  solution.  In  this  case  the  micro-crystals  are  long,  pris- 
matic needles,  often  in  stellate  or  fasciculated  groups.  They  may 
be  obtained  with  a  dilution  of  1  :  500.  These  crystals  belong  to  the 
rhombic  system,  and  may  be  hexagonal,  lozenge-shaped,  or  octa- 
hedra,  with  rhombic  bases.  Strychnine  gives  crystals  spontaneously 
with  a  dilution  of  1  : 200,  and  on  rubbing  with  a  1  :  1000  solution. 
In  this  case  the  micro-crystals  are  long,  prismatic  needles,  often 
in  stellate  or  fasciculated  groups.  They  may  be  obtained  with  a 
few  thousandths  of  a  milligramme  of  alkaloidal  salt  by  the  aid  of 
friction.  The  reaction,  therefore,  becomes  of  great  value  in  con- 
firming the  presence  of  these  two  alkaloids  in  toxicological  work,  as 
specially  for  the  presence  of  strychnine.  Narcotine  and  veratrine, 
in  presence  of  acetic  acid,  give  amorphous  precipitates  with  the 
reagent.  They  have  the  aspect  of  an  emulsion  of  spheroidal  cor- 
puscles. With  veratrine,  the  granular  formation  is  very  distinct  in 
a  dilution  of  1  : 200.  Drawings  are  given  of  the  typical  micro- 
crystals  of  the  perchlorates  of  strychnine '  and  of  brucine.  (G. 
