216 
Preparation  of  Pure  Chlorophyll. 
/Am.  Jour.  Pharm- 
t      April,  1884. 
ON  THE  PREPARATION  OF  PURE  CHLOROPHYLL. 
By  Dr.  A.  Tschircit. 
All  attempts  hitherto  made  to  prepare  pure  chlorophyll  must  be 
regarded  as  failures,  their  authors  having  started  with  the  idea  that 
chlorophyll  is  a  comparatively  stable  substance,  not  altered  by  treat- 
ment with  hydrochloric  acid,  etc.  But  an  exact  study  of  the  altera- 
tions produced  in  the  very  characteristic  spectrum  of  living  leaves  and 
of  alcoholic  chlorophyll  solutions,  by  the  action  of  various  reagents, 
shows  that  pure  chlorophyll  is  an  extremely  unstable  body,  which  is 
decomposed  even  on  treating  the  leaves  with  alcohol,  even  though  no 
alteration  of  color  is  thereby  produced.  Hence  it  follows  that  the 
substances  hitherto  described  as  "chlorophyll"  or  "crystallized  chlo- 
rophyll," and  obtained  either  by  treating  chlorophyll  extracts  with 
stroug  hydrochloric  acid,  and  precipitating  the  resulting  blue  solution 
(phyllocyanin)  with  excess  of  water1  or  with  marble2 — i.  e.,  by  ener- 
getic chemical  actions — or  by  absorbing  the  chlorophyll  from  its  alco- 
holic solution  with  animal  charcoal  and  washing  it  out  with  ether3 — 
must  be  regarded  as  products  of  decomposition  more  or  less  remote 
from  the  original  substance. 
This  conclusion  is  confirmed  by  spectroscopic  examination,  which 
shows  that  the  crystallized  chlorophyll  of  Gautier  and  Rogalski  is 
identical  with  the  chlorophyllan  of  Hoppe-Seyler  ("  Zeitschr.  PhysioL 
Chcm.,"  [3],  347),  which,  as  I  have  shown  ("  Ber.  der  deutsch.  botan. 
Gesellsch.,  [1],  145),  is  a  product  of  the  oxidation  of  chlorophyll,  and 
that  the  pure  chlorophyll  of  Berzelius,  Mulder  and  Pfaundler  is  iden- 
tical with  Fremy's  phyllocyanic  acid.4  Here,  then,  are  two  bodies 
which  agree  perfectly  in  their  absorption  spectra,  but — as  shown  by 
their  behavior  to  caustic  alkalis,  which  dissolve  phyllocyanic  acid, 
1  Berzelius  ("Annalen,"  [27],  298).— Harting  ("Pogg.  Ann.,"  [96],  547). 
—Pfaundler  (''Annalen,"  [115],  43). 
2  Mulder  ("J.  pr.  Chem.,"  [33],  479). 
3 Gautier  ("Comt.  rend.,"  [89]'  862).— Rogalski  ("Compt.  rend.,"  [90], 
881),  and  Role  de  la  chlorophylle  dans  r assimilation.— "  Inauguraldisserta- 
tion,"  Krakau. 
4  ("Compt.  rend.,"  [61],  191.)— I  here  designated  as  Phyllocyanic  acid 
only  the  body  formed  by  decomposition  of  phyllocyanin,  which  is  not 
identical  with  that  which  Fremy  obtained  by  treating  chlorophyll  with 
barium  hydroxide,  magnesia  or  alumina,  and  decomposing  the  resulting 
salts  with  acids. 
