NEW  INSTRUMENT  FOR  RAPID  FILTRATION  OF  LIQUIDS.  107 
Our  readers  would  do  well  to  consult  the  paper  of  Mr. 
Carter,  before  referred  to,  and  compare  his  results  with  those  of 
M.  Hubler.  Unless  we  admit  that  colchicum  contains  an  active 
alkaloid  in  its  cormus,  and  a  neutral  active  principle  in  its  seeds, 
we  cannot  reconcile  these  results,  because  the  processes  of  Carter 
and  Hubler  are  so  nearly  identical  that,  if  the  same  principle 
existed  in  both,  it  must  have  been  produced  in  each  case.  Mr. 
Carter's  alkaloid  we  have  seen,  handled,  and  tested,  as  to  its 
alkalinity,  and  reaction  with  sulphuric  acid  and  nitrate  of 
potassa.  As  Mr.  Carter  does  not  appear  to  have  treated  the 
seeds,  nor  Mr.  Hubler  the  cormus,  it  leaves  the  question  open 
for  new  investigations  which,  we  hope,  will  be  made,  and  settle 
this  vexed  question — vexed  because  we  have  four  experimenters, 
two  on  each  side  of  the  question  of  alkalinity.  Mr.  Carter's 
well-known  accuracy  leads  us  to  hope  that  he  will  resume  the 
subject,  and  apply  his  process  to  the  seeds  and  give  the  results. — 
Ed.  Am.  Jour.  Pharm. 
ON  A  NEW  INSTRUMENT  FOR  THE  RAPID  FILTRATION  OF 
L  QUIDS. 
By  Edward  Parrish. 
This  instrument  is  the  invention  of  A.  B.  Spencer,  of  Roches- 
ter, N.  Y.  Its  design  is  to  facilitate  filtration,  on  a  small  scale, 
by  producing  a  partial  vacuum  in  the  receiving  vessel,  and  thus 
rendering  the  pressure  of  the  atmosphere  available  in  forcing 
liquids  rapidly  through  suitable  media.  It  is  made  entirely  of 
hard  rubber,  and  is  neither  corroded  by  acids  or  alkaline  solu- 
tions, nor  by  alcoholic  or  ethereal  liquids.  Although  neither  the 
principle  nor  its  application  is  new,  the  use  of  this  material  in 
such  an  apparatus  constitutes  an  important  improvement,  and 
the  ingenious  adjustment  of  the  several  parts  leaves  nothing  to 
desire.  The  air-pump  consists  of  a  cylinder,  about  two  inches  in 
diameter  an  I  ten  inches  long,  upon  a  cast-iron  base,  secured  to 
the  table  or  counter  by  a  clamp  ;  the  piston,  which  works  in  this 
with  great  precision,  contains  a  valve  of  simple  construction.  It 
will  be  apparent  to  any  one  who  is  familiar  with  syringes  of  this 
material,  that  it  possesses  unusual  fitness  for  the  purpose ;  a 
highly  polished  surface,  with  just  sufficient  elasticity  to  allow  an 
