542  Valuation  of  Drugs  and  Foods.  {TovimD^X™' 
also  to  a  recent  paper  on  "The  Examination  of  Commercial  Flour," 
in  the  Jour.  Arner.  Chem.  Soc,  August,  1899. 
It  ought  to  be  mentioned,  however,  that  this  is  a  subject  which, 
as  shown  by  recent  communications  in  this  country  as  well  as 
abroad,  is  receiving  more  and  more  attention  (see  Pharm.  Review, 
Feb.,  1 899).  Microscopical  methods  for  the  quantitative  valuation  of 
drugs  may  be  divided  into  those  (1)  where  no  reagents  are  em- 
ployed and  (2)  in  which  micro-chemical  reactions  are  necessary. 
Under  Class  I  may  be  mentioned :  (a)  the  determination  of  a  for- 
eign starchy  adulterant  in  a  drug ;  (b)  the  number  of  secretion  cells, 
hairs  or  reservoirs  containing  oils,  resins  and  other  principles,  as  in  rhi- 
zomes and  leaves,  etc.,  containing  these  products;  (c)  in  determining 
the  number  of  sclerenchymatic  cells  or  fibres  or  other  characteristic 
cells  of  an  adulterant  or  admixture  in  a  drug  or  food.  This  is  par- 
ticularly applicable  in  the  study  of  the  spices,  some  foods,  as  tea, 
coffee,  cocoa,  as  well  as  in  drugs. 
No  doubt  upon  further  examination  a  very  important  relationship 
will  be  shown  to  exist  between  certain  cell-contents  and  the  active 
principles  in  drugs.  It  appears,  from  the  further  investigations  by 
Mr.  Heineberg,  that  there  is  a  ratio  in  jalap  between  the  percent- 
age of  resin  and  the  number  of  starch  grains  and  crystals  of 
calcium  oxalate.  The  following  table  gives  the  average  number 
of  crystals  and  starch  grains  found  in  a  mount  of  1  milligramme  of 
powdered  jalap.  The  per  cent,  of  resin  and  specific  gravity  of  the 
tubers  in  each  lot  had  also  been  determined. 
Sample. 
Per  Cent,  of 
Resin. 
Specific 
Gravity. 
Crystals  of 
Calcium 
Oxalate  in 
1  Milligramme. 
Starch  Grains 
in 
1  Milligramme. 
176 
1*194 
88 
357 
6-62 
1-360 
125 
140 
7-64 
1-297 
107 
178 
From  these  results  it  would  appear  that  the  microscopical  method 
for  determining  the  value  of  jalap  would  be  as  valuable  as  the 
method  of  specific  gravity. 
Probably  the  most  important  class  of  substances  that  require  a 
microscopical  examination  in  order  to  determine  their  value  are 
the   "  compound   powders,"    as    pulvis    glycyrrhizae  compositus, 
