Am'se0pt^' i893arm" }  Gleanings  from  the  German  Journals.  455 
precipitate  with  barium  chloride  solution.  After  drying,  the  com- 
pound forms  an  amorphous,  white  powder  insoluble  in  water  and 
alcohol,  but  soluble  in  both  water  of  ammonia  and  hydrochloric  acid. 
The  frequent  combination  in  prescriptions  of  zinc  oxide  and  boric 
acid  suggested  the  preparation. — W.  Koll,  Pharm.  Post,  1893,  338. 
The  iodine  absorption  of  fats  and  fixed  oils,  proposed  by  von 
Hiibl  which  has  proven  such  an  important  factor  in  the  study  of  this 
class  of  bodies,  despite  the  objectionable  feature,  first  announced  by 
its  originator,  of  the  continued  deterioration  of  the  standard  solu- 
tion, has  received  attention  from  a  number  of  sources  having  for 
their  object  the  correction  of  this  defect.  In  the  Am.  Jour.  Pharm., 
I893,  382,  P.  Welmans  proposes  a  mixed  solvent  of  ether  and  acetic 
acid.  Dr.  W.  Fahrion  (Chem'iker  Ztg.,  1893, 1 10°)  substituted  methyl 
alcohol  for  the  ethyl  alcohol  in  making  the  solution  and  examined 
the  solution  repeatedly  during  four  weeks;  the  decrease  in  strength, 
after  one  month's  standing  was,  for  the  ethyl  alcohol  solution,  33-6 
per  cent.,  while  for  the  methyl  alcohol  solution  it  amounted  to  only 
1 2'  1  per  cent.;  the  latter  lost  during  the  first  twenty-four  hours  ri 
per  cent.,  the  former  6-6  per  cent.  F.  Gautter  calls  attention  to  the 
mercuric  chloride  and  proves  that  apart  from  solvent  and  excess  of 
iodine,  which  had  previously  been  announced  as  matters  of  import- 
ance in  getting  trustworthy  results,  the  presence  of  the  mercuric 
chloride  in  varying  amounts  will  give  as  results,  variable  iodine 
absorption  figures,  the  greater  the  amount  of  mercuric  chloride  the 
higher  the  iodine  absorption  ;  probably  the  most  important  result 
obtained  was  that  in  the  presence  of  the  mercuric  chloride  the  satu- 
rated fatty  acids,  like  lauric  and  stearic,  absorbed  iodine.  For  these 
experiments  a  solution  of  iodine  in  carbon  tetrachloride  was  used,  the 
mercuric  chloride  was  dissolved  in  the  smallest  possible  quantity  of 
absolute  alcohol  and  diluted  with  carbon  tetrachloride  to  make  a  solu- 
tion of  5  gm.  in  100  cc;  this  introduced  very  little  alcohol  when  added 
to  the  iodine  solution.  Gautter  recommends  therefore  to  omit  the  mer- 
curic chloride  in  the  iodine  absorption  tests,  and  as  a  simply  alcoholic 
solution  acts  too  slowly,  he  suggests  an  iodine  solution  in  carbon 
tetrachloride  ;  this  solution  is  most  rapidly  made  by  stirring  or 
agitating  one  gram  iodine  with  small  portions  of  the  solvent  at  a 
time,  decanting  and  adding  another  portion,  etc.,  until  all  of  the 
iodine  is  dissolved  and  the  solution  measures  one  liter.  The  sodium 
thiosulphate  solution  is  made  by  dissolving  19-528  gm.  in  sufficient 
