236         Pharmaceutical  Colleges  and  Associations,  {hm£?J£™' 
The  phenomenon  was  explained  by  Mr.  Coulier  to  be  due  to  the  superficial  tension 
of  liquids,  which  has  been  studied  by  Mr.  Plateau. 
A  paper  on  Dragon  s  blood  and  its  falsifications,  by  Mr.  Henry  Bretet,  was  read. 
True  dragon's  blood  is  not  scratched  by  the  finger-nail,  yields  a  red,  non-adherent 
powder,  when  heated  gives  of  red  vapors,  and  is  found  to  contain  very  little  iron. 
False  dragon's  blood,  which  appears  to  be  made  by  mixing  oxide  of  iron  with  resin, 
differs  in  each  of  these  particulars,  but  sometimes  imparts  a  purple-red  color  to  alco- 
hol, proving  that  some  true  dragon's  blood  had  been  used  in  manufacturing  the 
imitation. 
Mr.  Guichard  made  some  remarks  on  fluid  and  syrupy  extracts,  and  noticed  more 
particularly  the  fluid  extracts  officinal  in  England  and  the  United  States.  For  con- 
venience in  dispensing,  he  has  used  for  some  time  preparations  which,  while  repre- 
senting solutions  of  solid  extracts,  are  prepared  by  concentrating  infusions  of  the 
drug  to  a  certain  extent,  adding  some  glycerin,  and  evaporating  until  the  residue 
represents  approximately  a  solution  of  one  part  of  extract  in  an  equal  weight  of 
glycerin.  The  author  prefers  this  method  to  the  solution  of  the  solid  extract  in 
glycerin  or  other  solvents,  and  regards  the  addition  of  some  glycerin,  even  to  ordi- 
nary extracts,  to  be  advantageous.  Mr.  Desnoix  coincided  with  these  views,  but 
Mr.  Mialhe  considered  the  addition  of  glycerin  unnecessary. 
Mr.  Petit  gave  a  summary  of  his  researches  of  the  action  of  pancreatin  upon  albu- 
minoid substances,  whereby  crystallizable  compounds,  leucin  and  tyrosin,  analogous 
to  the  products  of  excretion,  are  formed.  The  residue  from  the  action  of  pepsin 
upon  albuminoids  is  always  amorphous. 
At  the  meeting  held  March  ist,  a  note  by  Mr.  Frebault,  of  Meursalt,  was  read, 
on  the  use  of  alkaline  picramates  as  a  test  for  acids  and  alkalies.  The  picramates 
(dinitramidophenates)  of  the  alkalies  and  of  calcium  have  a  magnificent  red  color, 
which  by  free  acid  is  changed  to  greenish-yellow,  the  red  being  restored  by  an  alkali. 
A  solution  of  the  ammonium  salt  is  readily  obtained  by  acting  with  an  excess  of 
sulphhydrate  of  ammonium  upon  an  alcoholic  solution  of  picric  (trinitrophenic) 
acid.  The  calcium  picramates  keep  very  well,  and  may  be  employed  in  solution  or 
with  paper  like  litmus. 
Another  paper,  by  the  same  author,  was  on  The  action  of  iodine  upon  carminic  acid 
and  the  coloring  principle  of  logwood.  An  infusion  of  cochineal  with  distilled  water 
is  not  affected,  but  on  the  addition  of  a  little  alkali,  or  by  using  ordinary  water,  is 
instantly  decolorized.  The  same  reaction  takes  place  with  an  infusion  of  logwood. 
Free  acids  prevent  the  reaction  ;  the  most  convenient  reagent  is  a  solution  of  iodine 
in  potassium  iodide.  The  author  believes  this  reaction  to  be  available  for  the  rapid 
valuation  of  cochineal,  carmine  and  logwood,  and  for  the  estimation  of  iodine. 
Fuchsin  and  the  coloring  principles  of  red  poppy,  mulberries  and  wine  are  not 
decolorized. 
A  discussion  ensued  on  the  yield  of  extracts,  Mr.  Hoffmann  believing  that  notable 
differences  in  the  yield  from  the  same  material  were  not  obtained,  provided  the  pro- 
cess was  not  changed.  Mr.  Guichard,  however,  cited  the  experience  of  several 
authors,  proving  the  variability  of  the  yield. 
To  detect  the  presence  of  fuchsin  in  moine,  Mr.  Yvon  recommended  to  treat  the 
suspected  wine  with  animal  charcoal,  which  retains  the  fuchsin,  and  from  which  it 
may  be  afterwards  obtained  by  the  aid  of  alcohol. 
