8;6 
Nucleic  Acid. 
Am.  Jour.  Pharm. 
Dec,  1918. 
nucleic  acid."  It  is  with  this  plant  nucleic  acid  that  the  present  paper 
chiefly  deals. 
The  following  statement  shows  at  a  glance  the  chief  products  of 
hydrolysis  of  these  two  nucleic  acids,  and  at  the  same  time  affords 
an  insight  into  their  respective  chemical  constitutions  : 
Plant  Origin. — Guanine,  adenine,  cytosine,  uracil,  cf-ribose  (pen- 
tose), phosphoric  acid. 
Animal  Origin. — Guanine,  adenine,  cytosine,  thymine,  lsevulinic 
acid  (from  a  hexose),  phosphoric  acid. 
Plant  nucleic  acid  is  a  white  friable  substance  devoid  of  odor  or 
taste,  and  having  the  formula  C38H50O29N15P4.  It  is  practically  in- 
soluble in  water,  but  dissolves  readily  in  solutions  of  alkaline  ace- 
tates. It  is  also  readily  soluble  in  solutions  of  the  alkalies  forming 
the  soluble  alkaline  salts.  From  these  solutions  a  few  drops  of 
hydrochloric  acid  precipitate  the  nucleic  acid  in  a  dense  curdy  form, 
which  dissolves  completely  on  the  addition  of  a  large  excess  of  the 
acid. 
When  acetic  acid  is  added  to  a  solution  of  the  sodium  salt,  the 
acid  is  partly  precipitated,  but  no  precipitate  is  formed  on  the  addi- 
tion of  any  acid  in  the  presence  of  a  sufficient  quantity  of  alkaline 
acetate. 
When  added  to  a  solution  of  sodium  nucleate,  a  solution  of 
copper  acetate  acidified  with  acetic  acid  gives  a  bulky  greenish-blue 
precipitate. 
Calcium  chloride  in  excess  in  the  presence  of  a  few  drops  of 
acetic  acid  gives  a  white  precipitate  at  first  flocculent,  quickly  be- 
coming more  granular. 
Silver  nitrate,  when  added  in  considerable  excess  to  a  fairly 
strong  and  neutral  solution  of  sodium  nucleate,  gives  a  white  gelat- 
inous precipitate.  On  the  addition  of  a  little  sodium  chloride  this 
dissolves,  forming  an  opaque  colloidal  solution.  One  drop  of  hydro- 
chloric acid  added  to  this  precipitates  the  silver  as  chloride. 
Solutions  of  sodium  nucleate  in  water  exhibit  a  marked  tendency 
to  gelatinize,  and,  if  sufficiently  strong,  set  to  a  jelly. 
The  above  reactions,  coupled  with  the  recognition  of  guanine 
and  adenine  (which  are  the  most  easily  isolated  and  best  defined  of 
the  bases  formed  on  hydrolysis),  suffice  for  the  identification  of 
nucleic  acid,  when  it  exists  in  a  fairly  pure  condition. 
For  the  hydrolysis  of  nucleic  acid  10  grm.  of  the  acid  (or  a 
