GLEANINGS  FROM  THE  FRENCH  JOURNALS.  303 
mohitleine,  and  that  the  blue  color  is  due  to  the  formation  of  mo- 
hitlie  acid  which,  combined  with  alkaline  bases  of  the  salts  con- 
tained in  the  water,  yields  the  blue  color.  The  latter  statement 
needs  corroboration. — Jour,  de  JPharm.,  Avril,  1866. 
Erythrocentaurin. — M.  C.  Mthu  describes  (Jour,  de  Pharma- 
cie,  Avril,  1866,  p.  265,)  this  principle  as  existing  in  Erythrcea 
eentaurium  as  neutral,  colorless,  inodorous  and  tasteless.  It 
fuses  at  277°  F.,  is  not  volatile,  and  crystallizes  on  cooling.  At 
a  higher  temperature  it  is  consumed  without  residue.  It  is  solu- 
ble in  1630  parts  of  cold  and  35  parts  of  boiling  water,  and  in 
48  parts  of  ordinary  alcohol  at  60°  F.,  in  13  parts  of  chloroform 
and  in  245  parts  of  strong  ether.  Fixed  and  volatile  oils,  ben- 
zine, and  sulphuret  of  carbon,  dissolves  it  readily,  and  much  more 
hot  than  cold.  It  is  remarkably  indifferent  to  acids  and  alkalies. 
SO3,  dissolves  it  in  quantity,  without  being  colored,  and  the  ad- 
dition of  water  precipitates  it  in  crystals.  Neither  nitric,  muri- 
atic nor  chromic  acids  have  any  action  upon  it,  nor  have  the 
mineral  alkalies.  Chlorine,  bromine  and  iodine  are  without  ac- 
tion on  it  at  the  ordinary  temperature,  but  chlorine  at  its  fusing 
point  changes  it.  Oxide  of  silver,  tannin,  creasote,  bisulphite  of 
soda,  acetate  of  lead,  chlorides  of  platinum,  mercury  and  iron  do 
not.  It,  however,  acts  on  permanganate  of  potassain  the  cold.  Its 
composition  is,  Carbon  67*66,  Hydrogen  5*09,  Oxygen  27*25  per 
cent,  which  corresponds  with  the  formula  C27  H12  08. 
The  most  remarkable  property  of  erythrocentaurin  is  that  of 
being  rapidly  colored  rose  color  by  the  solar  rays,  the  coloration 
being  rapid  in  proportion  to  the  intensity  of  the  light.  This  re- 
markable phenomenon  is  purely  physical ;  it  occurs  whether  the 
crystals  be  in  air  hydrogen,  sulphuretted  hydrogen,  bicarburetted 
hydrogen,  carbonic  oxide  or  carbonic  or  sulphurous  acids.  After 
coloration  it  is  not  altered  in  weight,  and  on  solution  in  any  of 
its  solvents  becomes  again  colorless.  It  also  becomes  colorless 
at  270°  F.,  and  then  is  susceptible  to  the  same  action  of  light. 
The  author  has  studied  the  influence  of  light  on  this  substance 
very  elaborately,  and  results  of  great  interest  have  been  devel- 
oped. He  finds  only  the  most  refrangible  rays  of  the  spectrum 
are  active  in  modifying  erythrocentaurin,  and  that  analogous 
