Am.  Tour.  Pharm. 
May,  19 1 S. 
Urinary  Antisepsis. 
347 
to  be  a  great  obstacle.  It  may  be  readily  seen  that  the  compound, 
the  antiseptic  power  of  which  is  due  to  its  acid  or  basic  properties, 
would  become  inert  in  urine  on  account  of  the  buffer8  value  of  the 
urinary  salts.  Other  compounds,  containing  ionic  silver,  become 
inert  in  urine  because  the  silver  is  precipitated  by  the  chlorids. 
There  remain,  however,  a  large  number  of  drugs  whose  loss  of  anti- 
septic strength  in  urine  is  due  to  some  unknown  interfering  action, 
the  nature  of  which  is  as  yet  undetermined.  It  must  not  be  under- 
stood that  this  loss  of  antiseptic  power  in  urine  is  noted  after  the 
compound  has  been  passed  through  the  animal  body,  but  it  occurs 
when  urine  is  added  to  the  aqueous  solution  of  the  compound  in  a 
test  tube.  For  this  reason  it  became  necessary  to  carry  on  parallel 
germicidal  tests  both  in  urine  and  in  water. 
The  colon  bacillus  was  used  throughout  the  experiments  because 
it  is  the  most  frequent  invader  of  the  urinary  tract,  and  because 
it  is  resistant  to  antiseptics,  and  is  readily  cultivated.  Investigations 
with  other  organisms  are  to  be  carried  on  in  the  future.  Each  com- 
pound was  studied  with  the  view  of  determining  (1)  its  germicidal 
properties  (in  water  and  in  urine)  and  (2)  its  antiseptic  or  in- 
hibitory properties  in  urine. 
1.  Germicidal  Test. — In  order  to  rule  out  a  large  number  of  un- 
desirable compounds,  it  was  necessary  to  establish  an  arbitrary 
standard  of  germicidal  strength,  and  compare  them  all  with  phenol 
(carbolic  acid).  The  arbitrary  method  chosen  was  the  determina- 
tion of  the  highest  dilution  of  each  compound  which,  in  1  Cc. 
amount,  will  kill  one  loop  (3  Mm.  internal  diameter)  of  a  twenty- 
four-hour  broth  culture  of  the  colon  bacillus,  in  one  hour,  at  37 0  C. 
Dilutions  of  the  drug  were  made  with  sterile  pipets  in  sterile  test 
tubes,  and  all  but  1  Cc.  of  each  dilution  was  discarded.  After  the 
inoculation  of  each  dilution  with  one  loop  of  colon  bacilli,  and  in- 
cubation for  one  hour,  0.1  Cc.  of  each  dilution  was  transferred,  to 
melted  agar,  and  plated.  In  transferring  these  0.1  Cc.  amounts,  it 
was  found  convenient  to  use  capillary  pipets  drawrn  out  (from  3 
Mm.  glass  tubing)  long  enough  to  reach  the  bottom  of  the  test 
tubes.    By  connecting  the  large  end  of  one  of  these  capillary  tubes 
8  The  term  "  buffer  "  action  refers  to  the  ability  of  mixtures  of  certain 
acid  and  alkaline  salts  in  solution  to  maintain  a  practically  constant  hydrogen 
ion  concentration,  in  spite  of  the  addition  of  moderate  amounts  of  acid  or 
alkali.  For  detailed  discussion,  see  publications  of  Henderson  and  Palmer, 
Clark  and  Lubs,  and  Shohl  and  Janney. 
