462                 Cardiac  Stimulants  and  Depressants.  { A™  ctobw"  1910™" 
Preparation                                  Drug  Fluidextract          Tincture  Extract 
Aconite  root                         0.0100  0.0100            0.100  0.002 
Aconite  leaf  0.0150  0.0150            0.150  0.00375 
Gelsemium   ............  0.25  0.375              2.5  0.100 
Veratrum                              0.05  0.05               0.5  0.015 
Feeling  that  perhaps  the  standard  lethal  doses  of  the  drugs 
referred  to  in  this  paper  might  be  more  clearly  understood  if  they 
were  stated  in  a  manner  similar  to  that  in  use  in  describing  the 
strength  of  bacterial  toxins, — that  is,  by  stating  the  number  of 
units  contained  in  a  cubic  centimetre  of  a  standard  preparation, 
we  suggest  the  following  system,  namely,  that  the  unit  in  this 
case  be  the  amount  required  to  kill  one  gramme  of  animal  (guinea 
pig).  By  this  method  of  calculation  we  have  prepared  the  following 
table : 
Preparation                                    Drug            Fluidextract  Tincture  Extract 
Aconite  root                          25,000            25,000  2,500  125,000 
Aconite  leaf                           16,600             16,600  1,660  66,000 
Apocynum                                3,300              3,300  330 
Convallaria                             3,300              3>300  330 
Digitalis                                  2,500              2,500  250  10,000 
Gelsemium                              1,000                660  100  2,500 
'1800 
1000 
Squill  <^  330 
1  goo 
500 
Strophanthus   100,000           100,000  10,000 
Veratrum                            .    5,000              5,000  500  16,600 
Of  the  drugs  tabulated  in  the  preceding  portion  of  this  com- 
munication only  the  following  are  sufficiently  accurately  provided 
with  chemical  assay  processes  to  enable  us  to  make  comparisons : 
digitalis ;  aconite  root ;  aconite  leaf  ;  gelsemium  ;  veratrum. 
Digitalis. — Attention  is  first  called  to  the  article  by  Reed  and 
Vanderkleed  on  the  standardization  of  digitalis  preparations,  pub- 
lished in  the  March,  1908,  number  of  the  American  Journal  of 
Pharmacy.  There,  on  page  119,  is  given  a  table  showing  the 
relationship  between  chemical  assay  for  digitoxin  and  physiologic 
assay  based  upon  lethal  dose  for  guinea  pigs,  for  nine  prepara- 
tions. During  the  past  year,  the  results,  as  shown  in  the  following 
table  indicate  that  the  minimum  lethal  doses  as  obtained  by  Dr. 
Reed  two  years  ago  were  slightly  smaller  than  those  obtained  by 
Dr.  Githens  during  the  past  year,  when  compared  with  the  results 
