Preparation  of  Arsphcnamine.  {Am'MTa0vurToPToarm' 
1919. 
arsphenamine  that  about  50  per  cent,  of  the  arsphenamine  made  does 
not  meet  the  Surgeon  General's  requirements4  and  therefore  is  not 
distributed. 
In  studying  the  subject,  I  came  to  the  conclusion  that  the  toxicity 
of  arsphenamine  or  at  least  the  variation  of  the  toxicity  is  largely 
due  to  the  use  of  methyl  alcohol  and  ether  in  the  final  precipitation 
of  the  base  as  the  dihydrochloride.  While  most  chemists  use  Ehr- 
lich  and  Bertheinrs  methyl  alcohol  and  ether  method  or  some  modi- 
fication of  it  for  precipitating  the  dihydrochloride  of  salvarsan,  not 
one  will  admit,  or  is  willing  to  believe,  that  the  dry  product  contains 
a  molecule  of  methyl  alcohol. 
The  theoretical  amount  of  arsenic  in  arsphenamine  as  shown  by 
the  formula  is  34.2  per  cent.,  assuming  that  it  is  absolutely  pure  and 
contains  no  water  or  solvent  in  its  crystal  or  solid  form. 
As  As 
/\ 
ci         x/  n 
OH  OH  ~ 
The  German  firm  having  a  monopoly  of  the  manufacture  of  the 
drug,  tried  at  first  to  get  the  scientific  public  to  accept  its  state- 
ment unchallenged  of  a  34  per  cent,  arsenic  content.  Analyses  by 
others  soon  compelled  them  to  abandon  that  claim  and  for  seven 
years  31.6  per  cent.  (31.57  per  cent.)  has  been  and  now  is  accepted 
as  the  arsenic  content. 
This  different  and  smaller  content  of  arsenic  is  in  harmony  with 
an  assumption  of  two  "  molecules  of  water  of  crystallization  "  in  the 
final  dry  substance. 
This  amount  of  water  is  given  in  the  literature  frequently  and 
by  the  U.  S.  Health  Service  regulations5  as  an  actual  fact, 'and  a 
higher  content  of  arsenic,  involving  less  solvent  combined  with  the 
drug,  is  looked  upon  with  suspicion. 
I  believe  I  have  exhausted  the  references  to  the  literature  on  this 
point,  and  I  can  find  no  justification  for  assuming  two  molecules  of 
water  in  the  drug,  made  by  the  usual  and  original  directions. 
4  The  U.  S.  Public  Health  Service,  P.  H.  Reports,  33,  540,  1918,  requires 
an  M.L.D.  of  0.060  g./kilo  body  weight,  while  the  Surgeon  General  (recently) 
raised  the  requirement  to  0.080  g./kilo,  and  to  0.100  g./kilo. 
5  Public  Health  Reports,  33,  540,  1004,  1918. 
