Am.  Jour.  Phartn.) 
April,  1920 J 
Current  Literature. 
271 
canned  in  sugar  form  suitable  mediums  for  the  growth  of  B.  botuUnus 
and  the  development  of  its  toxin.  Peaches,  apricots  and  pears  were 
tested.  Certain  of  the  methods  of  canning  are  inefficient  if  the  raw 
material  happens  to  be  contaminated  with  spores  of  B.  hotulinus. 
This  is  true  of  commercial  canners'  processes  as  well  as  of  the  home 
canning  processes.  {Arch.  Intern.  Med.,  Chicago;  through  /.  Am. 
Med,  Assoc.,  January  10,  1920.) 
Modification  of  Benzidine  Test  forOccui.tBi,ood. — Gregersen 
has  recently  found  that  a  frequent  cause  of  failure  in  the  appHcation 
of  the  benzidine  test  is  that  too  strong  solutions  of  the  reagent  are 
used.  Following  Grundmann's  idea,  he  reached  the  conclusion 
that  many  of  the  positive  reactions  in  normal  persons  on  a  meatless 
diet  may  be  explained  by  the  fact  that  mineral  traces  of  blood  were 
mixed  with  the  feces,  which,  because  of  the  excessive  sensitiveness 
of  the  reagent,  produced  positive  reactions.  Boas  accepts  the  idea 
that  the  use  of  highly  concentrated  benzidine  solution  doses  lead  to 
false  diagnosis,  and  on  that  account  approves,  after  careful  trials, 
Gregersen's  modification  of  the  test.  Gregersen  uses  a  0.5  per  cent, 
benzidine  solution,  and  instead  of  the  easily  decomposable  hydrogen 
dioxide  he  employs  barium  dioxide,  which  is  much  more  stable, 
Gregersen's  method  is  described  in  detail,  and  Boas  offers  what  he 
considers  a  further  slight  improvement.  Boas  admits,  however, 
that  in  using  the  weaker  solution  very  slight  hemorrhages,  though 
worthy  of  note,  might  go  undiscovered.  {Berliner  klinische  Woch.; 
from  Jour.  Amer.  Med.  Assoc.,  January  24,  1920.) 
Determination  of  Fiucic  Acid. — Perrin  {Repertoire  de  Pharma- 
cie.  No.  3,  19 1 9)  states  that  it  is  essential  to  determine  the  amount 
of  filicic  acid  present  in  extract  of  male  fern,  as  many  an  extract  may 
have  the  required  content  of  filicin,  without  containing  a  trace  of 
filicic  acid,  the  essentially  active  constituent.  He  employs  the  fol- 
lowing method:  to  the  crude  filicin,  in  the  weighed  flask,  obtained 
according  to  the  directions  given  in  the  B.  P.,  add  2  Cc.  of  amylic 
alcohol,  allow  the  mixture  to  stand  for  twenty-four  hours,  well 
corked,  shaking  occasionally.  Thereupon,  drop  by  drop,  20  Cc. 
of  pure  methyl  alcohol  are  added ;  the  first  drops  produce  a  precipitate 
which  redissolves;  when  the  precipitate  does  not  redissolve  the  re- 
mainder of  the  methyl  alcohol  may  be  added  at  once.  Shake,  let 
the  mixture  stand  for  twenty -four  hours  in  a  cool  place;  filter,  wash 
