Am.  Jour.  Pharm. 
Dec,  1918. 
Nucleic  Acid. 
875 
NUCLEIC  ACID  AND  ITS  ANALYTICAL  EXAMINATION.1 
By  A.  Chaston  Chapman,  F.I.C. 
During  recent  years  nucleic  acid  and  certain  of  the  metallic 
nucleates  have  found  somewhat  wide  and  increasing  application  in 
medicine,  and  particularly  in  connection  with  surgical  practice.  At 
the  outbreak  of  war,  these  substances  were  obtained  chiefly  from 
Germany  and  America,  and  so  far  as  I  am  aware  were  not  manu- 
factured at  all  in  this  country.  A  number  of  urgent  enquiries  hav- 
ing been  received  from  France  and  elsewhere,  the  Pharmaco-Chem- 
ical  Products  Company,  Ltd.,  suggested  to  me  that  I  should  under- 
take the  investigation  of  this  matter  with  the  object  of  devising 
methods  for  the  manufacture  of  pure  nucleic  acid  and  its  derivatives 
on  a  large  scale.  Yeast  was  obviously  the  most  convenient  raw 
material,  and  for  more  than  a  year  the  above-mentioned  company 
have  been  manufacturing  considerable  quantities  of  pure  yeast- 
nucleic  acid  and  its  compounds. 
It  will  be  obvious  that,  in  the  prosecution  of  this  work,  it  was 
necessary  to  have  methods  for  examining  the  products  obtained  and 
to  establish  analytical  criteria  of  purity.  The  production  of  pure 
nucleic  acid  on  a  large  scale  presents  many  difficulties,  the  two  chief 
ones  being  the  complete  removal  of  protein  and  the  prevention  of 
the  contamination  of  the  acid  with  the  products  of  its  own  decompo- 
sition. This  will  be  at  once  apparent  when  it  is  remembered  that 
nucleic  acid  results  from  the  breaking-down  of  the  nucleo-proteins 
of  the  cell  nuclei  on  the  one  hand,  and  that,  on  the  other,  it  yields, 
as  the  result  of  further  hydrolytic  change,  a  number  of  complex 
nucleosides  and  bases,  together  with  phosphoric  acid  and  the  carbo- 
hydrate d-ribose.  The  conditions  for  hydrolysis  have  therefore  to 
be  very  exactly  determined  and  very  strictly  observed  in  practice. 
Up  to  the  present  two  nucleic  acids  have  been  very  fully  studied, 
the  one  derived  from  yeast,  the  other  from  the  thymus  gland. 
Whether  these  two  acids  represent  typical  members  of  two  sharply 
defined  groups,  or  whether  all  nucleic  acids  are  identical  with  the 
one  or  the  other,  is  at  present  a  little  doubtful.  The  latter  view  is, 
however,  the  one  more  generally  held,  and  the  nucleic  acid  from 
yeast  is  frequently  known  by  the  more  comprehensive  term  "  plant- 
1  From  The  Analyst,  July,  191 8. 
