ADecSberP1i9OTm*}      Opsonic  Theory  and  Tuberculosis,  563 
As  is  well  known  all  biological  products  deteriorate  in  the  course 
of  time.  Smallpox  vaccine  kept  at  the  temperature  of  the  body  is 
valueless  after  a  very  few  days.  According  to  Elgin  it  may  be  kept 
for  years  at  a  temperature  of  about — 50  C.  without  the  least  impair- 
ment of  strength.  Our  own  experiments  have  shown  us  that 
diphtheria  antitoxin,  under  the  ordinary  conditions  of  the  market, 
loses  about  2  per  cent,  of  its  potency  per  month.  When  kept  at 
a  little  above  the  freezing  point  the  deterioration  is  practically  nil. 
We  have  no  way  of  gauging  the  activity  of  bacterial  vaccines  and 
no  method  of  accurately  determining  the  loss  in  strength  on  keep- 
ing, but  we  do  know  that  there  is  some  loss,  and  we  know  that 
temperature  and  light  are  the  most  active  influences  in  this  direction. 
The  lesson  to  be  learned  from  this  is  that  all  biological  products 
should  be  kept  as  near  the  freezing  point  as  possible,  and  the  phar- 
macist who  displays  packages  of  antitoxin  and  vaccines  in  his  shop 
window,  or  keeps  them  in  a  show  case,  is  what  our  President  might 
call  an  undesirable  citizen,  not  so  much  from  the  standpoint  of  the 
manufacturer,  as  of  the  patient  who  must  suffer  the  result  of  not  receiv- 
ing the  full  benefit  of  a  product  which  had  been  kept  under  proper 
conditions.  An  efficient  refrigerator  is  absolutely  necessary  in  every 
drug  store  which  handles  biological  products.  This  necessity  will 
increase  with  the  increase  of  our  knowledge  of  immunity.  For 
specific  infections  drugs' will  be  used  less  and  less  and  the  use  of 
specific  curative  and  immunizing  materials  will  increase  in  pro- 
portion. 
THE   OPSONIC  THEORY   IN  RELATION   TO  TUBER- 
CULOSIS. 
By  E.  Burviu>Hoi,mes, 
Bacteriologist,  Phipps  Institute,  Philadelphia. 
Wrhen  I  accepted  the  invitation  to  appear  before  you,  I  was  under 
the  impression  it  was  but  to  discuss  the  paper  of  Dr.  Hitchens,  to 
which  you  have  just  listened.  When,  three  or  four  days  later,  I 
received  a  printed  card  announcing  that  I  should  read  a  paper  on 
"  The  Opsonic  Theory  in  Relation  to  Tuberculosis,"  I  can  assure 
you  it  came  as  a  surprise.  As  a  matter  of  fact,  had  I  been  apprised 
of  this  in  the  first  place,  I  should  have  indubitably  declined  the 
honor,  and  for  the  one  good  reason  that  I  should  have  felt,  as  I  do 
