Am* April'  ^J"111'  }    Chemical  Reaction  of  Diphtheria  Antitoxin.  165 
The  L  -f-  dose  of  the  toxin  (0.42  Cc.)  was  treated  with  0.42  n/10 
HC1  and  let  stand  in  the  thermostat  for  T/2  hour,  then  neutralized 
with  0.42  n/10  NaOH.  This  preparation  killed  a  guinea  pig  in  24 
hours,  the  same  time  as  the  untreated  toxin.  Evidently  weakening 
of  the  toxin  by  acid  was  not  the  cause  of  the  survival  of  the  guinea 
pigs  after  injection  of  the  toxin  mixed  with  platinum  nitrate  from 
the  globulin  preparation. 
To  see  if  an  excess  of  acidity  was  the  cause  of  the  inactivity  of 
the  second  test,  1  Cc.  of  preparation  II  was  mixed  with  1  Cc.  HC1 
n/10  placed  in  an  incubator  for  Yi  hour,  then  neutralized  with 
NaOH.  This  was  then  diluted  to  20  Cc,  i.  e.,  to  theoretically  cor- 
respond to  the  dilution  in  the  second  platinum  experiment.  One 
Cc.  of  this  solution  protected  against  one  L-j-  dose  of  the  toxin, 
thus  showing  that  this  amount  of  acid  did  not  destroy  the  anti- 
toxin. 
As  a  control  test,  7.5  Cc.  of  platinum  chloride  (10  per  cent.) 
were  diluted  to  100  Cc.  with  distilled  water  and  while  warm  were 
saturated  with  H2S.  On  filtering  this  gave  a  solution  perhaps  darker 
in  color  than  the  preceding  active  platinum  filtrate.  This  color 
was  due  to  the  presence  of  a  trace  of  platinum-  sulphide,  Injections 
were  made  of  1  Cc,  2  Cc,  and  3  Cc  but  these  did  not  kill,  or  even 
sicken,  the  guinea  pigs.  Of  this  solution,  1  Cc.  and  2  Cc.  were  each 
mixed  with  one  L-f  dose  of  the  toxin  diluted  as  usual,  and  placed 
in  the  incubator  for  one  half  hour.  Even  1  Cc  protected  against 
one  L  +  dose  of  the  toxin,  showing  that  the  protection  was  due  to 
the  small  amount  of  platinum  present  and  that  the  antitoxin  had  not 
been  freed.  This  action  must  presumably  have  been  due  to  some 
catalytic  action  of  the  platinum  as  the  concentration  was  presumably 
too  weak  to  precipitate  any  of  the  toxin.  These  results  may  sug- 
gest a  therapeutic  use  for  platinum  compounds. 
From  our  review  of  the  literature  and  from  our  own  work  at 
present  we  find  no  chemical  proof  that  a  separation  of  antitoxin  and 
globulin  can  be  made,  although  Banzhaf 's  work  and  that  of  Hurwitz 
and  Meyer  might  suggest  it. 
Note. — Several  of  the  guinea  pigs  on  which  the  platinum  ex- 
periments were  made  developed  abscesses. 
