Am.  Jour.  Pharm.  1 
Nov  ,  1883.  / 
Minutes  of  the  Pharmaceutical  Meeting. 
587 
microscope  made  by  Messrs.  Watkins  &  Hill,  of  Charing  Cross,  London. 
Mr.  Wilder  supposes  that  it  is  about  90  or  100  years  old.  It  could  not  be 
older  than  230  years,  as  the  field  glass  was  introduced  about  the  year  1650  ; 
the  Lieberkuhn  proves  it  could  not  have  been  made  before  1738,  when  that 
appendage  was  first  made;  an  instrument  quite  similar  to  this  is  figured 
on  Plate  XII,  fourth  edition  of  Micrograph ia,  in  1771,  and  induces  the  opinion 
that  it  is  not  older  than  1780  ;  the  funnel-shaped  bod^^  was  continued  to  be 
used  down  to  the  year  1810 ;  all  the  lenses  are  single  ones,  no  compound 
lenses  were  made  before  1819.  The  stand  can  be  inclined  for  the  conveni- 
ence of  the  student.  Upon  motion,  which  was  seconded,  the  thanks  of 
the  meeting  were  returned  to  Mr.  Wilder  for  this  interesting  addition  to  the 
cabinet  of  apparatus  belonging  to  the  College. 
Professor  Maisch  exhibited  Koenig's  Chart  of  Food  Substances,  the  vari- 
ous components  of  which,  and  their  percentage,  nutritive  value,  ash,  and 
moisture  are  represented  by  lines  of  diflferent  tints,  the  fat  being  shown 
by  yellow  color,  the  carbo-hydrates  by  blue,  and  nitrogenated  matter  by 
red  ;  the  proportion  required  for  difl[*erent  ages  is  also  given  upon  the  chart. 
Mr.  Berry  exhibited  a  Pressure  Percolator.  The  peculiarities  of  the 
apparatus  are  thatthe  drug  to  be  treated  is  secured  between  two  diaphragms 
of  phosphor  bronze,  drawn  together  by  a  double  screw  of  the  same  mate- 
rial. When  arranged,  it  is  placed  in  the  percolator,  which  has  a  funnel  at 
the  lower  portion  and  a  close  top  into  which  a  tube  is  secured  ;  to  this  tube 
a  gum  hose  is  fastened,  which  connects  with  a  reservoir  elevated  to  any 
desired  height;  the  rapidity  of  the  flow  is  determined  by  a  stopcock 
attached  to  the  reservoir  and  a  pinchcock  constricting  the  gum  hose.  It 
is  claimed  that  the  last  portions  of  alcohol  can  be  removed  from  the  drug 
without  mixing  with  the  water  employed  to  force  it  through. 
In  the  discussion  which  followed  the  exhibition,  Prof.  Maish  showed 
that  mere  pressure  percolation  was  by  no  means  new,  in  fact  it  was^the 
oldest  method  of  percolation.  Count  Real's  filter  press,  which  was  first 
publicly  noticed  in  1816,  and  is  described  in  Mohr,  Redwood  and  Procter's 
Pharmacy,  was  constructed  in  such  a  way  as  to  secure  pressure  by  a  column 
of  liquid.  Boullay  had  experimented  very  fully  on  the  subject  and,  in  1833, 
announced  that  he  could  accomplish  all  he  desired  without  pressure,  by  care- 
fully observing  the  necessary  conditions.  After  the  perfection  of  the  process 
of  displacement  in  the  United  States,  the  old  and  abandoned  process  had 
again  been  brought  forward  and,  two  years  ago,  Mr.  Rosenwasser  had  intro- 
duced a  percolator  (see  Amer.  Jour.  Phar.  1881,  p.  568),  from  which  the  one 
now  exhibited  did  not  differ,  except,  perhaps  in  the  material  used  for  and  the 
manner  of  fastening  the  diaphragms.  The  new  feature  of  Rosenwasser's 
percolator,  as  compared  with  Real's  filter  press,  consisted  in  the  confining 
of  the  vegetable  powder,  so  as  to  prevent  its  expansion  beyond  a  certain 
limit,  after  having  been  moistened.  But  Prof.  Maisch  thought  that  critical 
experiments  as  to  the  complete  exhaustion  of  the  powder  under  such  a 
condition,  had  as  yet  not  been  made. 
A  member  of  the  class  present  asked  the  attention  of  the  meeting  to  the 
fact  that  packages  of  some  American  made  Carbonate  of  Magnesiuniy 
marked  four  ounces,  were  short  in  weight ;  some  of  them  weighing  but 
