508 
Cholera-red  and  Ptomaines. 
f  Am.  Jour.  Pharm. 
(.        Oct.,  1887. 
"  CHOLERA -EED  AND  PTOMAINES  FROM  GELATIN."1 
By  Dr.  Brieger. 
Pohl  discovered,  in  1886,  that  when  sulphuric  acid  is  added  to  cul- 
tures of  the  comma  bacillus  a  red  color  is  produced  ;  a  fact  which  may 
be  utilized  in  identifying  the  bacillus.  The  coloring  matter  is  named 
cholera-red,  and  the  present  communication  deals  with  the  origin 
of  this  material ;  the  investigation  being  possible  only  after  a  con- 
siderable amount  of  the  coloring  matter  had  been  obtained.  The 
cholera-red,  which  may  be  obtained  pure  by  recrystallization  from 
benzol,  is  soluble  also  in  ether,  amylic  alcohol,  and  chloroform.  Ex- 
tremely characteristic  for  cholera-red  is  its  conversion  into  a  blue  col- 
oring matter  in  presence  of  a  certain  definite  amount  of  alkali,  a  shade 
of  color  which  passes  again  directly  into  burgundy  red,  on  the  addi- 
tion of  a  mineral  acid.  The  blue  coloring  matter  is  readily  dissolved 
in  amylic  alcohol,  but  on  standing,  changes  to  the  original  color. 
When  the  chemically  pure  cholera-red  is  distilled  in  a  tube  along  with 
zinc  dust,  a  white  crystalline  substance  is  sublimated  over  on  to  a  part 
of  the  tube  kept  cold.  This  substance  has  precisely  the  odor  of  indol, 
and,  dissolved  in  water,  gives  the  characteristic  red  color  of  indol.  It 
follows  that  cholera-red  is  a  derivative  of  indol.  Moreover  cholera 
cultures  on  albuminous  soils  contain  indol,  as  may  be  ascertained  in 
the  following  manner :  when  these  cultures  are  distilled  over  with 
acetic  acid,  and  the  distillate  treated  with  fuming  sulphuric  acid,  the 
nitrous  indol  color  mentioned  above  as  characteristic,  is  struck.  Which 
derivative  of  indol  cholera-red  is  will  be  determined  when  material 
has  accumulated. 
The  second  part  of  the  paper  concerns  itself  with  ptomaines  pro- 
duced in  gelatin  by  the  action  of  bacteria.  Nencki  in  1876  distilled 
over  some  gelatin  which  had  been  putrified  by  contact  with  the  pan- 
creas of  an  ox,  and  obtained  from  the  distillate  by  means  of  baryta 
water  along  with  trimethylamine  a  ptomaine   of  the  composition 
CH3 
C8Hn  N,  which  he  held  to  be  isophenylethylamine  C6H5 — CH  < 
NH2 
The  author  has  obtained  from  putrefactive  mucus  neuridine  C5H14N2, 
dimethylamine  NH  (CH3)2  and  in  a  very  slight  amount  a  poisonous 
ptomaine  whose  action  resembled  that  of  muscarine.    He  has  also 
1  Deutsche  medicinische  Wochenschrift,  June  2,  1887;  abstract  by  Jas.  Niven, 
in  Med.  Chronicle,  September. 
