Am'  jS?y,"  Sarm' }  Gleanings  from  the  German  Journals.  331 
will  dissolve  saturated  and  unsaturated  fatty  acids  but  will  not  dis- 
solve the  oxidation  products  of  the  latter  ;  the  oxalic  acid  produced 
by  the. oxidation  of  the  glycerin  remains  in  the  aqueous  solution 
and,  hence,  does  not  interfere.  Ten  gm.  of  the  fat  placed  in  a  capsule 
of  1*5  litre  capacity  are  saponified  with  10  gm.  sodium  hydrate  dis- 
solved in  alcohol ;  after  the  evaporation  of  the  alcohol  the  soap  is 
dissolved  in  about  one  litre  water,  the  solution  heated  to  the  boiling 
point  and  dependent  upon  the  iodine-figure,  from  10-25  gm.  potas- 
sium permanganate  in  5  per  cent,  solution  added,  the  mixture  boiled 
for  a  short  time,  filtered,  the  filtrate  acidified  with  hydrochloric 
acid  and  allowed  to  cool;  the  precipitate  is  collected  upon  a  linen 
strainer,  thoroughly  expressed  and  perfectly  extracted  with  petro- 
leum-ether;  the  remaining  insoluble  portion  consists  of  the  oxida- 
tion products  of  the  unsaturated  fatty  acids  which  are  insoluble  or 
only  slightly  soluble  in  water ;  for  the  detection  of  these  water- 
soluble  oxidation  products  the  acid  filtrate  after  the  oxidation  must 
also  be  examined  according  to  directions  to  be  given  later.  The 
oxidation  products  are  as  follows:  Dioxy stearic  acid  (from  oleic 
acid)  crystallizes  in  rhombic  plates,  insoluble  in  water,  easily  soluble 
in  hot  alcohol,  difficultly  soluble  in  cold  alcohol  and  ether  ;  melting 
point  136-5°,  solidifying  point  119-1220  C. 
Trioxy stearic  acid  (from  ricinolic  acid)  crystallizes  from  boiling 
water  in  microscopic  needles,  insoluble  in  cold  water,  benzol,  carbon 
disulphide,  petroleum-ether  and  chloroform,  difficultly  soluble  in 
ether  and  cold  alcohol,  easily  soluble  in  hot  alcohol  and  glacial 
acetic  acid  ;  melts  at  140-1420  C.  Isotrioxy stearic  acid  (from  ricini- 
solic  acid)  differs  from  the  preceding  by  its  easy  solubility  in  ether 
and  a  lower  melting  point,  110-1110  C.  Tetroxy stearic  acid  or 
sativic  acid  (from  linolic  acid)  appears  under  the  microscope  as  long 
needles  or  prisms  ;  melts  at  1730,  soluble  in  2,000  parts  of  boiling 
water,  insoluble  in  cold  water,  ether,  carbon  disulphide  and  chloro- 
form, difficultly  soluble  in  cold  alcohol,  easily  soluble  in  glacial  acetic 
acid  and  hot  alcohol.  He xaoxy stearic  acid  or  linusic  acid  (from 
linolenic  acid)  rhombic  plates  or  needles  melting  at  203-205°  C. 
more  soluble  in  water  than  sativic  acid,  difficultly  soluble  in  alcohol, 
insoluble  in  ether.  Isolinusic  acid  (from  isolinolenic  acid)  prismatic 
needles  melting  at  173-175°  C,  difficultly  soluble  in  cold  water, 
easily  soluble  in  alcohol  and  boiling  water,  insoluble  in  ether, 
benzol,  carbon  disulphide  and  chloroform.    (Benedikt,  Analyse  der 
