270 
A  Nev)  Percolator. 
f  Am.  Jour. Pharm. 
1      Nov.,  1881. 
fastened  to  the  body  of  the  percolator  by  any  simple  contrivance.  I 
have  it  secured  by  a  lock  and  key,  working  on  an  eccentric  (not  shown 
in  the  dniwing),  which  firmly  holds  the  diaphragm  in  any  position 
made  necessary  in  the  cylinder  by  the  varying  height  of  the  drug. 
The  bottom  plate,  H,  Fig.  2,  Ij,  Fig.  1,  is  easily  secured  to  the 
body  of  the  cylinder,  and  the  bottom  or  outlet  tube  is  easily  closed 
with  a  cork  or  rubber  tube  and  pinch-cock.  Now,  the  percolator  hav- 
ing been  packed  very  tightly  on  the  bottom,  and  less  so  proceeding 
upward,  the  diaphragm  holding  the  drug  in  place  having  a  piece  of 
muslin  or  filtering  medium  placed  between  it  and  the  drug,  we  are 
ready  to  reverse  the  percolator,  attach  it  to  the  menstruum  reservoir, 
C,  Fig.  1,  by  means  of  the  tube  E,  Fig.  1,  and  suspend  it  by  the  han- 
dle of  the  menstruum  reservoir.  The  percolator  is  ready,  the  men- 
struum is  poured  into  the  reservoir,  the  opening  to  which  is  closed 
with  a  notched  cork,  and  percolation  begins. 
Now,  as  the  drug  is  held  in  place  on  all  sides,  so  that  it  cannot 
•expand  beyond  its  limits,  it  presses  within  upon  itself,  so  as  in  some 
instances  to  be  almost  solid  ;  thus  the  greatest  possible  compactness  is 
secured,  and,  as  the  height  of  the  column  of  liquid  increases  the  pres- 
sure and  velocity  of  the  liquid  increases,  we  have  called  into  play  a 
force  that  can  compete  with  lateral  pressure,  no  matter  how  much 
this  may  increase  by  the  subsequent  swelling  of  the  drug;  thus  perco- 
lation can  now  go  on  at  the  will  of  the  operator,  not,  as  heretofore,  at 
the  will  of  the  drug.  Instead  of  being  obliged  to  unpack  the  perco- 
lator and  re-pack  it  more  loosely,  it  is  only  necessary  to  increase  the 
height  of  the  tube  and  reservoir. 
On  account  of  the  compactness  we  can  give  to  the  drug,  and  its 
inability  to  swell  in  any  direction  but  upon  itself,  only  a  minimum 
quantity  of  liquid  will  be  able  to  lodge  between  the  cells  and  within 
them,  so  that,  instead  of  being  able  to  absorb  and  retain  by  capillary 
and  osmodic  attraction  the  usual  large  amount  of  menstruum  before  a 
drop  comes  through,  the  amount  absorbed  is  reduced  to  a  minimum, 
and  with  many  drugs  long  before  the  full  quantity  of  liquid  (1  pint 
for  16  troy  ounces)  is  used  the  liquid  begins  to  drop. 
With  this  percolator,  it  is  easily  seen  no  waste  in  alcohol  or  other 
menstruum  occurs,  since  we  can  overcome  by  pressure  what  heretofore 
had  to  be  overcome  by  a  liquid  occasioning  less  pressure  and  of  greater 
Mmpidity ;  thus  water  can  be  forced  through  the  drug  in  spite  of  its 
expanding  the  cells. 
