212 
Tincture  of  Strophanthus. 
Am.  Jour,  Pharm. 
May,  1909. 
Several  samples  of  standardized  tinctures  made  by  the  large 
manufacturing  houses  were  tested  in  the  same  way,  and  their  tox- 
icity indicated  that  they  contained  only  7.1  milligrammes  of  com- 
mercial strophanthin  per  cubic  centimetre,  or  less  than  80  per  cent, 
of  that  in  an  equivalent  amount  of  a  10  per  cent,  tincture  which 
fully  represented  the  seed  used  in  the  above  experiments  (10 
milligrammes). 
There  is  nothing  in  the  literature  which  justifies  the  claim  of 
such  a  high  percentage  of  strophanthin  as  these  experiments  indi- 
cate. Yet  we  must  insist  that  there  is  the  toxic  equivalent  of  about 
10  per  cent,  of  commercial  strophanthin  in  the  seeds  which  were 
used.  Whether  the  former  analyses  depending  upon  chemical 
reactions  have  been  inaccurate,  whether  the  seeds  used  have  not 
been  of  the  same  strength,  or  whether  there  exists  in  the  seed  some 
substance  having  a  synergistic  action, — these  considerations  must 
be  left  for  future  investigations.  That  the  physiological  method  of 
estimating  toxicity  is  sufficiently  accurate  for  practical  purposes 
has  been  proved.* 
The  following  statements  are  based  upon  more  than  sixty  experi- 
ments, all  upon  cats,  by  which  the  minimal  lethal  dose  has  been 
determined  for  each  tincture. 
Tincture  No.  1  fully  represented  the  seed. 
Tincture  No.  2.  The  first  half,  obtained  by  145  hours  of  perco- 
lation and  339  hours  of  maceration,  contained  85  per  cent,  of  the 
active  principle,  and  the  second  half  15  per  cent. 
Tincture  No.  3  fully  represented  the  seed. 
Tincture  No.  4  was  about  20  per  cent,  weaker  than  No.  5.  The 
curve  of  percolation  is  given  below. 
Tincture  No.  5  fully  represented  the  seed.  As  compared  with 
No.  4,  it  is  evident  that  these  two  percolations  are  on  either  side  of 
*A  cat-unit  is  the  minimal  lethal  dose  by  vein  per  kilo  of  cat.  If  the 
injection  be  made  subcutaneously,  then  the  minimal  lethal  dose  will  be  some- 
what greater  (about  one-fourth  greater)   (Hatcher  and  Bailey"). 
Injections  should  be  so  diluted  that  the  dose  can  be  easily  measured. 
If  one-half  cubic  centimetre  or  more  of  an  alcoholic  tincture  is  to  be  tested, 
the  alcohol  should  be  evaporated. 
The  accuracy  of  this  method  of  standardization  may  be  judged  from  the 
following  experiment.  The  toxicity  of  the  six  portions  of  tincture  No.  4 
were  separately  determined,  and  the  results  added  together.  Then  one- 
tenth  of  each  of  the  six  was  taken,  these  were  mixed,  and  the  resulting 
mixture  tested.    The  error  was  less  than  10  per  cent. 
