404  Gleanings  from  the  German  Journals.  {AauAug*iSo*rm' 
Croton  oil  and  Croton-olic  acid. — Professor  Robert  and  one  of  his 
scholars  have  finished  an  investigation  deciding  the  question  of  the 
differences  in  croton  oil  and  its  action,  (i)  Commercial  croton  oil ; 
(2)  acid  croton  oil,  the  portion  soluble  in  alcohol ;  (3)  neutral  croton 
oil j  the  portion  only  slightly  soluble  in  alcohol,  and  (4)  pure  croton- 
olic  acid  were  examined  for  their  activity.  The  crotonolic  acid  was 
prepared  by  taking  a  strongly  acid  commercial  oil,  extracting  the 
portion  soluble  in  alcohol  and  treating  this  with  an  excess  of  hot- 
saturated  solution  of  baryta  for  one-half  hour  on  a  water  bath ;  the 
white  mass  formed  is  thoroughly  washed  with  water  to  remove 
excess  of  baryta,  coloring  matter  and  salts  of  acetic,  butyric  and 
tiglic  acids,  drained,  completely  dried  in  a  vacuum  and  extracted 
with  ether.  The  barium  salts  of  lauric,  palmitic  and  stearic  acids 
are  insoluble,  while  those  of  oleic  and  crotonolic  acids  are  soluble ; 
the  latter  two  salts  are  separated  by  evaporating  the  ether,  treating 
the  residue  with  absolute  alcohol,  which  dissolves  the  crotonolate 
of  barium  only  ;  on  cautiously  adding  sulphuric  acid,  filtering  and 
evaporating,  croton-olic  acid  is  obtained. 
No  definite  solubility  in  absolute  alcohol  can  be  ascribed  to 
croton  oil,  the  solubility  depending-upon  the  age  of  the  oil,  i.  <?.,  the 
presence  of  croton-olic  acid,  some  samples  of  old  oil  containing  no 
glyceride  of  croton-olic  acid,  but  only  the  latter  in  the  free  state. 
The  activity  of  the  samples  disclosed  the  following :  The  commer- 
cial and  acid  oils  as  well  as  croton-olic  acid,  used  in  experiments 
upon  animals,  had  less  effect  than  upon  the  human  being,  but 
diarrhoea  followed  the  use  of  the  three  samples.  The  neutral  oil, 
the  activity  of  which  upon  man  was  confirmed,  failed  to  produce 
any  effect  upon  animals.  Experiments  go  to  prove  that  the  pan- 
creatic ferment  has  the  power  of  liberating  croton-olic  acid  from  the 
neutral  oil.  The  introduction  into  the  blood  vessels  of  sodium 
carbonate  emulsions  of  the  commercial  oil  produced  serious  poison- 
ing symptoms  in  quantity  of  8  mg.  to  I  kilo  weight  of  the  animal ; 
acid  croton  oil  was  more  poisonous,  requiring  less  than  5  mg.  for  1 
kilo  ;  and  of  croton-olic  acid  the  lethal  dose  is  less  than  4  mg.  for  1 
kilo.  Sodium  croton-olates,  obtained  from  acid  or  neutral  oil,  were 
identical ;  hence,  the  conclusion  of  Senier?  that  the  alcohol  soluble 
portion  of  croton  oil  represents  a  peculiar  oil-modification,  is  no 
longer  tenable. 
Interesting  is  the  fact  that  insane  persons,  like  animals,  are  not 
