202  Alcoholic  Extract  of  the  Root  of  Atropa  Belladonna.  { Ami^r-  £&£rm- 
Examination  of  Commercial  Specimens. — The  amount  of  alkaloid 
in  various  commercial  extracts  was  now  determined,  with  the  follow- 
ing results . — 
Analyses  of  the  Alcoholic  Extracts  of  the  Root  of  Atropa  Belladonna 
met  with  in  Commerce. 
Per  cent,  of 
Per  cent,  of 
Per  cent,  of 
Number  of  extract. 
alkaloid  in 
alkaloid  in 
water. 
normal  extract. 
dry  extract. 
I. 
1-75 
2-08 
16-0 
II 
1-85 
2-36 
21-4 
III 
3-0 
3-60 
16-8 
IV  ... 
4-45 
5-67 
21-6 
V 
3-20 
4-0 
20-0 
VI. 
3-65 
4-4 
16-8 
'  vii  
3-0 
3-55 
16-0 
VIII 
36 
4-28 
16-0 
IX 
1-65 
2-04 
177 
The  quantity  of  alkaloid  has  been  calculated  in  the  normal  extract 
that  is  in  the  preparation  as  prescribed  and  dispensed,  and  therefore 
indicates  the  difference  in  strength  which  is  experienced  in  actual 
practice.  The  quantity  of  alkaloid  has  also  been  calculated  in  the  dry 
extract  to  admit  of  an  accurate  comparison  of  the  variations  in  alka- 
loidal  content  which  arise  from  causes  other  than  differences  in  con- 
sistence. 
The  great  variations  which  these  analyses  disclose  can  scarcely  be 
entirely  due  to  a  corresponding  variation  in  the  alkaloidal  content  of 
the  root.  They  are,  no  doubt,  in  great  part  due  to  differences  in  the 
method  of  preparing  the  extract,  and  especially  to  the  relative  quan- 
tities of  alcohol  and  water  which  are  employed.  The  method  of  the 
British  Pharmacopoeia  consists  in  percolating  with  alcohol  and  sub- 
sequently with  water  to  displace  the  spirit.  The  water  dissolves  from 
the  root  much  albuminoid  and  mucilaginous  matter  left  undissolved 
by  the  spirit  and  the  extract  will  be  greater  in  bulk,  though  weaker  in 
alkaloid,  than  wThen  alcohol  alone  is  used  and  removed  from  the  marc 
with  a  filter-press. 
An  extract  was  prepared  from  a  specimen  of  root  (containing  about 
*3  per  cent,  of  total  alkaloid)  with  alcohol  alone.  It  contained  2*8  per 
cent,  of  total  alkaloid.  When  an  extract  was  prepared  as  directed  by 
the  British  Pharmacopoeia,  only  1*7  percent,  of  alkaloid  was  found  in 
the  product.    Hence  it  is  clear  that  in  order  to  prepare  extracts  that 
