152 
ON  RUMICINE. 
ly  passes  to  the  state  of  ferridcyanide,  which  resists  the  action 
of  the  permanganate. 
Urea  is  oxidised  with  great  difficulty ;  after  boiling  for  a 
whole  day,  it  only  furnishes  small  quantities  of  nitrate. 
Gelatine  is  readily  acted  upon  in  the  cold,  forming  carbonate 
and  nitrate  of  potash,  besides  a  peculiar  salt  of  potash,  which 
acquires  a  bright  red  color  when  heated  to  392° — 572p  F. 
Pyroxyline  is  acted  upon  when  boiled,  as  are  also  nitronaph- 
thaline  and  nitrobenzine.  In  these  three  cases  a  considerable 
quantity  of  crystallized  nitrate  of  potash  was  obtained. 
Nitronapthaline  also  furnished  a  salt  presenting  the  charac- 
ters of  phthalate  of  potash,  the  product  which  is  obtained  when 
naphthaline  is  oxidized  by  permanganate  of  potash. 
Nitrobenzine  furnished  a  salt  crystallizing  in  large  rhomboi- 
dal  laminae,  containing  an  acid  which  is  but  sparingly  soluble  in 
cold  water. 
Of  course  the  oxidation  of  the  nitrated  derivatives  may  fur- 
nish products  different  from  those  obtained  by  the  oxidation  of 
the  bodies  forming  these  derivatives.  The  oxidation  of  the  ni- 
trated derivatives  may  even  be  more  easy  than  that  of  the  origi- 
nal substances. 
In  general  it  is  difficult  to  foresee  whether  a  given  body  will 
reduce  permanganate  of  potash  with  more  or  less  difficulty. 
Thus  oxide  of  chrome,  precipitated,  washed,  and  dried  at  the 
ordinary  temperature,  reduces  the  permanganate  in  the  cold, 
forming  chromate  of  potash  and  oxide  of  manganese.  By  ebul- 
lition the  reduction  is  complete  in  a  few  minutes,  which  it  would 
have  been  impossible  to  predict  from  the  known  properties  of 
hydrated  oxide  of  chrome.- — Ibid,  from  Comptes  Rendus,  Nov. 
2,  1858. 
ON  RUMICINE. 
By  Karl  von  Thann. 
The  object  of  this  investigation  was  to  show  the  identity  of 
rumicine  with  the  chrysophanic  acid  discovered  by  Rochleder 
and  Held  in  Parmelia  parietina. 
Eumicine  was  first  prepared  in  1831  by  Buchner  and  Herber- 
