648  United  States  Pkarmacopoeial  Revision.  { ^Sptember^ Y920: 
The  use  of  the  second  pipette  and  the  conical  glass  vessel  is  no 
doubt  recommended  because  it  is  impossible  to  force  the  preparation 
into  the  lymph  sac  by  blowing  and  at  the  same  time  accurately 
measure  the  dose  to  the  hundredth  of  a  Mil. 
The  two  pipettes  and  the  conical  glass  vessels  should  be  replaced 
by  an  all-glass  or  Record  Tuberculin  Syringe,  which  is  graduated 
in  hundredths  of  a  Mil.  By  the  use  of  one  of  these  syringes  the 
actual  amount  of  the  preparation  injected  can  be  measured  to  the 
hundredth  of  a  Mil.,  whereas  by  the  U.  S.  P.  method  we  only  know 
the  amount  of  solution  placed  in  the  conical  vessel  and  not  the 
amount  actually  injected. 
On  page  608,  first  line,  the  directions  state: 
"The  dose  thus  found  is  then  compared,  etc." 
The  text  fails  to  state  which  dose  is  the  dose  to  be  compared. 
It  is  not  stated  anywhere  that  the  smallest  or  minimum  dose  neces- 
sary to  bring'  about  the  end  reaction  is  the  one  to  be  used  in  com- 
puting the  strength  of  the  preparation.  In  other  words,  the  direc- 
tions give  no  definite  outline  for  carrying  out  the  tests,  but  take  it  for 
granted  that  the  operator  understands  the  technique  of  giving  the 
doses  in  series,  progressively  increasing  or  decreasing  until  the 
M.L.D.  or  M.S.D.  is  found,  etc. 
Suprarenal  Gland. — As  stated  by  Hamilton,^  "the  biologic  assay 
of  products  of  the  suprarenal  gland  is  open  to  criticism  in  only  two 
particulars,  i.  e.,  in  the  method  of  measuring  and  administering  the 
doses  and  in  attempting  to  check  the  results  as  described." 
"Using  both  femoral  veins  for  injecting  sample  and  standard  is 
to  obviate  the  possible  mixing  of  the  two  solutions  if  both  are  in- 
jected into  the  same  vein.  But  it  introduces  a  very  much  greater 
source  of  error.  The  amount  injected  can  much  more  easily  be 
measured  by  use  of  a  pipette  than  in  a  syringe,  and  the  dose  after 
being  injected  can  be  easily  and  completely  washed  into  the  blood 
stream  by  a  follow-up  injection  of  2  Mils,  of  ph3^siologic  salt  solution. 
When  this  procedure  is  followed,  no  mixing  of  two  injections  is 
possible." 
Another  very  good  method  is  to  expose  the  saphenous  vein  at  its 
junction  with  the  femoral.  When  giving  injections,  the  needle  of  an 
all-glass  syringe  is  inserted  far  enough  through  the  saphenous  vein 
to  allow  the  point  to  project  directly  into  the  blood  stream  in  the 
femoral  vein.  After  injecting  the  preparation,  the  needle  can  be 
*  Hamilton:  "Biological  Standardization,"  This  Journal,  February,  1917^ 
