560  Gleanings  from  the  German  Journals.  {Am,IJJv.r;wSfEm" 
tilled  water,  5  gm.  According  to  the  writer,  the  copper  in  these 
mixtures  plays  the  part  of  a  "  specific,"  whilst  the  phosphorus  is  a 
"  dynamizing  agent." 
Bichromate  of  Aniline,  according  to  Girard  and  L'Hote,  [Arch, 
de  Pharm.,  October  5),  may  be  produced  in  well-defined  crystals,  as 
follows :  Two  saturated  solutions  are  prepared,  one  of  hydrochlorate 
of  aniline,  and  one  of  bichromate  of  potassium,  sodium,  ammonium  or 
calcium.  The  solutions,  in  equal  volumes,  should  be  mixed  while  very 
cold.  Very  numerous  yellow  crystals  are  thus  formed  which  are 
then  freed  with  water  from  all  traces  of  alkaline  chloride,  and  dried 
in  vacuo.  The  substance  thus  obtained  is  found  by  Girard  and 
L/Hote  to  have  the  formula  C12H4  (NH3)  2Cr03.  This  bichromate 
of  aniline  is  sparingly  soluble  in  cold  water  (about  4  to  1000)  and  is 
decomposed  by  boiling  water.  It  is  slightly  soluble  in  alcohol  which 
it  slowly  transforms  into  aldehyde.  When  dry  it  undergoes  no 
change ;  when  moist  it  changes  greatly  under  the  influences  of  light 
and  air.  It  decomposes  under  slight  elevations  of  temperature,  and 
burns  in  contact  with  flame  or  under  the  stroke  of  a  hammer.  It  in- 
flames also  in  contact  with  fuming  nitric  acid ;  with  sulphuric  acid  it 
burns  like  pyrophoric  copper.  Treated  with  cold  water  it  gives  rise  to 
violet  tints ;  treated  with  hydrochlorate  of  aniline  and  aniline  in  excess 
similar  colorations  are  obtained.  The  authors'  purpose  is  to  study 
the  coloring  matters  resulting  from  these  changes. 
GLEANINGS  FROM  THE  GERMAN  JOURNALS. 
By  John  A.  Martin,  Ph.g. 
Tannin  with  sodium  bicarbonate. — A  mixture  somewhat  like  the 
following :  Tannin  acid,  3 ;  water,  180 ;  solution  of  sodium  bicarbonate, 
sufficient  for  perfect  neutralization,  is  often  prescribed  in  Germany, 
and,  according  to  Pharm.  Ztg.,  generally  a  stumbling-block,  on 
account  of  it  soon  changing  to  a  dark  color,  particularly  when  there 
is  an  excess  of  alkali.  To  make  it  remain  uniform  for  a  long  time, 
expel  the  excess  of  carbonic  acid  in  sodium  bicarbonate  solution  by 
boiling,  and  the  tannin  solution,  diluted  as  much  as  possible  (in  pro- 
portion of  sod.  bicarb.,  1 ;  tannic  acid,  5)  is  added  to  the  former,  after 
cooling.    (Rundschau,  1887,  p.  447). 
Effect  of  alcohol  on  pepsin. — To  determine  the  question  whether 
