146  The  Opsonins  and  Bacterial  Vaccines.  {AmMi?ch,So7.raj" 
(1)  "  Isolate  in  pure  culture  the  causative  microorganism." 
(2)  "  Estimate  the  opsonic  power  of  the  patient's  blood  to  this 
microorganism." 
(3)  "  If  the  opsonic  index  be  at  or  below  normal,  prepare  and 
standardize  a  vaccine  from  this  microorganism." 
(4)  "  Inoculate  the  patient  with  this  vaccine  with  appropriate 
doses  and  at  proper  intervals,  as  shown  by  a  systematic  estimation 
of  the  opsonic  content  of  the  patient's  blood." 
PREPARATION  OF  VACCINES. 
The  vaccines,  with  the  exception  of  the  tubercle  vaccine,  consist 
of  emulsions  of  heated  cultures  of  the  particular  germ  producing  the 
infection.  Luxuriant  cultures  of  the  desired  organism  are  grown 
upon  inclined  agar  ;  the  growth  is  then  removed  with  salt  solution 
and  a  glass  rod,  and  thoroughly  emulsified  by  shaking  in  a  test-tube, 
in  order  to  get  the  germs  well  distributed  and  the  clumps  broken 
up.  The  number  of  germs  in  a  given  quantity  of  the  emulsion  is 
then  determined  by  comparing  the  number  of  germs  and  red  blood- 
corpuscles  in  a  mixture  of  one  part  emulsion,  one  part  freshly  drawn 
blood,  and  three  parts  of  normal  salt  solution.  If  there  are  ten  times 
as  many  germs  as  blood-corpuscles,  trie  bacterial  suspension  con- 
tains approximately  45,000,000  germs  per  cubic  centimeter.  The 
number  of  germs  present  will  of- course  vary  with  the  density  of  the 
emulsion.  The  bacterial  suspension  is  heated  at  the  lowest  temper- 
ature and  for  the  shortest  possible  time  to  kill  it.  The  amount  of 
sterilization  will  differ  with  different  organisms ;  6o°  C.  or  less 
maintained  for  thirty  minutes  or  less  is  usually  sufficient.  Cultures 
from 'the  vaccine  are  finally  made  to  insure  that  it  is  sterile  and  safe 
and  some  preservative  added. 
Tubercle  Vaccine. — This  is  the  "  New  Tuberculin  Koch,"  an  opa- 
lescent fluid,  containing  the  active  principle  of  tuberle  bacilli  ob- 
tained according  to  the  method  of  Koch. 
THERAPEUTIC  APPLICATION. 
After  a  proper  diagnosis  has  been  made,  the  patient's  opsonic 
index  taken,  and  the  appropriate  vaccine  prepared,  the  patient 
receives  his  initial  injection  of  several  hundred  millions  more  or  less 
of  the  heated  bacteria,  and  his  opsonic  index  is  watched.  A  short 
time  after  the  inoculation  is  made  the  opsonic  index  falls  lower  than 
