482  Microscopical  Examination  of  Cloves.  {A  oc?o0bUerrj894rm' 
the  non-conformity  in  results  of  analytical  chemists  in  organic  and 
even  in  inorganic  analyses,  unless  by  practice  the  individual  masters 
the  difficulties.  And  again,  it  has  been  recently  said,  "  that  in  the 
case  of  the  deterioration  of  vegetable  drugs  through  atmospheric 
influences  or  age,  as  well  as  in  the  adulteration  of  a  genuine  with 
inferior  drugs,  the  difficulty  of  determining  with  the  microscope  the 
respective  extent  of  change  or  adulteration  is  almost  insuperable." 
This  may  seem  to  be  so,  and  while  chemical  analysis  is  necessary, 
still  there  are  many  cases  where  the  quantitative  determination  of 
admixtures  and  adulterations,  if  they  are  to  be  determined,  can  be 
done  so  only  by  means  of  the  microscope. 
It  would  not  be  a  hard  matter  to  prepare  a  lengthy  paper  on  the 
difficulties  attendant  upon  research  in  this  direction.  Was  there 
anything  more  difficult  a  few  years  ago  than  the  study  of  bacteria  ? 
Not  until  Koch  devised  a  convenient  and  comparatively  easy  method 
for  this  kind  of  investigation,  did  this  department,  which  to-day  is 
recognized  as  a  branch  in  science,  become  so  popular.  Even  the 
medical  student  of  the  first  and  second  year  is  taught  to  recognize 
and  diagnose  the  insignificant  bacillus  tuberculosis. 
As  has  been  said  before,  this  paper  is  but  a  preliminary  one,  and 
while  the  author  has  been  at  work  upon  the  subject  for  some  time, 
the  work  has  been  done  under  rather  disadvantageous  circumstances, 
and  it  is  presented  at  this  meeting  to  elucidate  a  principle,  and  pre- 
sent the  results  of  what  may  be  an  incomplete  method,  for  your  consid- 
eration. The  method  of  procedure  is  as  follows :  A  measured  quantity 
(about  -200  gram)  of  substance  is  thoroughly  mixed  with  a  measured 
amount  (2  or  3  cubic  centimetres)  of  water.  One,  two  or  three 
drops,  formed  on  the  finger,  of  this  mixture,  are  placed  in  the  slide 
and  covered  with  a  cover-glass,  In  the  eye-piece  of  the  microscope 
is  slipped  a  piece  of  glass,  corresponding  to  an  ocular  micrometer, 
containing  100  square  millimeters.  By  a  little  practice,  a  slide  may 
be  prepared  that  is  fairly  uniform,  or  uniform  places  upon  it  may  be 
selected.  This  being  done,  then  a  count  is  made  of  the  number  of 
starch  grains,  fibres,  or  characteristic  tissue  in  the  spurious  sub- 
stance, contained  in  100  square  millimetres,  and  the  same  compared 
with  a  genuine  sample.  For  instance,  mixtures  were  made  of  genu- 
ine cloves  with  potato -starch,  wheat-starch,  cedar- wood,  turmeric, 
and  it  was  observed  that  quantitative  relations  by  comparison  do,  to 
some  extent,  hold  even  in  this  crude  way  of  prccedure.  In  deter- 
mining the  oil  a  slightly  different  method  was  pursued. 
