Febr°uUarV\  imS*'}    Recent  Literature  Relating  to  Pharmacy.  83 
spring  at  the  above-mentioned  health  resort.  They  spring  from  the 
ground,  are  of  a  brilliant  green,  and  are  sometimes  50  cm.  high. 
Some  are  found  floating  on  the  surface  of  the  water  in  green,  viscid, 
round  masses.  On  decaying  they  show  their  albuminoid  nature  by 
evolution  of  hydrogen  sulphide  and  ammonia,  as  well  as  forming, 
on  heating,  cyanides  and  ammonium  compounds. 
Their  ash  contains  iodine,  fluorine  and  silicon — elements  found 
in  the  surrounding  rocks  and  in  the  spring  water. 
As  in  seaweed,  the  iodine  percentage  is  much  higher  than  it  is 
in  the  water  in  which  they  float. 
For  this  reason,  the  plant,  which  is  unctuous  to  the  touch,  due  to 
the  silicon  it  contains,  has  been  used  as  a  poultice  and  used  by 
friction. 
The  author,  after  stating  that  the  plant  contains  98  per  cent,  of 
water,  and  that  desiccation  without  putrefaction  is  difficult,  recom- 
mends its  preservation  by  rapid  drying  in  a  current  of  warm  air 
and  powdering.  H.  V.  Arny. 
ASSAY  OF  MEDICATED  GAUZE. 
G.  Schacherl  read  a  paper  on  this  subject  before  the  Third  Inter- 
national Congress  of  Applied  Chemistry  (Pharm.  Post,  1898,437). 
Iodoform,  he  finds,  is  best  estimated  by  heating  the  gauze  in  a 
pressure  flask  on  a  water  bath,  with  solution  of  sodium  alcoholate 
in  alcohol,  whereby  the  iodoform  is  decomposed  and  the  iodine  con- 
verted into  sodium  iodide.  The  contents  of  the  bottle  is  poured 
into  a  beaker,  the  gauze  washed  with  water  and  the  washings  mixed 
with  the  alcoholic  liquid,  the  mixture  being  heated  to  concentrate 
it  and  to  drive  off  the  alcohol. 
The  cooled,  concentrated  liquid  is  mixed  with  diluted  nitric  acid 
(nitrous  free),  a  definite  quantity  of  normal  silver  nitrate  is  added 
and  an  aliquot  part  is  titrated  with  decinormal  potassium  sulpho- 
cyanate  solution,  whereby  through  the  excess  of  silver  nitrate  thus 
formed,  the  utilized  quantity  of  that  reagent  can  be  reckoned  ;  its 
factor  being  0.01309  grammes  iodoform  for  each  cubic  centimetre 
decinormal  silver  nitrate  employed.  Other  methods  of  assay — even 
gravimetric  estimation  as  silver  iodide — he  found  unsatisfactory  be- 
cause of  evaporation  of  the  volatile  iodoform  and  iodine. 
Carbolic  acid  he  assays  by  Koppeschaar's  method,  treating  the 
gauze  with  water  at  6o°  C,  withdrawing  an  aliquot  part,  which  is 
titrated  with  decinormal  bromine  solution. 
