170  Liquor  Cresolis  Compositus.         { A%Jp™r;iXarm* 
Seven  samples  of  cresol  were  obtained  from  various  sources,  repre- 
senting articles  of  German,  English  and  American  manufacture. 
These  were  examined  as  to  the  boiling  point,  specific  gravity,  and 
solubility,  after  which  samples  of  the  compound  solution  were  made 
from  each  one  of  them  and  the  properties  compared. 
The  Pharmacopceial  requirements  on  these  points  are  as  follows  : 
Boiling  point  195  to  2050  C;  specific  gravity  1-032  at  250  C;  soluble 
in  60  parts  of  water  at  25  0  C.  A  sample  of  crude  carbolic  acid  was 
included  in  the  list  for  purposes  of  comparison  (see  No.  4). 
Sample. 
Specific  Gravity. 
Boiling  Point. 
Solubility. 
I. 
197-203  C. 
I-70 
2. 
1-037 
192-201  c. 
I-60 
3- 
i'Q45 
194-201  C. 
I-60 
4- 
0-979 
188-268  c. 
insoluble 
5.  Amer. 
1*0383 
194-203  c. 
1-60 
6.  Eng. 
1-0363 
194-203  c. 
1-80 
7.  Ger. 
1-0316 
195-204  c. 
1-100 
These  figures  indicate  that  so  far  as  the  boiling  point  is  con- 
cerned, all  of  the  samples  are  very  close  to  the  U.  S.  P.  require- 
ments, but  that  as  regards  solubility  and  specific  gravity  there  is 
quite  a  variation  from  the  official  figures.  This  variation  may  in 
part  be  due  to  the  varying  proportions  of  the  three  isomers  which 
go  to  make  up  the  official  substance. 
In  connection  with  the  test  for  solubility  it  was  noticed  that  not 
one  of  the  samples  made  a  perfectly  bright  clear  solution,  but  that 
all  contained  varying  proportions  of  a  flocculent  material  which  was 
not  dissolved  even  after  the  addition  of  a  large  excess  of  water  and 
standing  for  some  time.  The  point  of  complete  solubility  was  there- 
fore taken  as  the  point  when  there  was  neither  a  milky  turbidity 
nor  the  separation  of  oily  drops.  All  of  the  cresol  samples 
answered  the  U.  S.  P.  requirements  for  absence  of  hydrocarbon  oil 
by  being  perfectly  soluble  in  sodium  hydroxide  solution. 
The  consideration  of  the  solutions  was  then  taken  up,  and  sam- 
ples of  the  solution  were  made  up  according  to  the  U.  S.  P.  direc- 
tions from  Nos.  1  and  2.  It  was  noticed  that  a  preparation  was 
afforded  which  was  not  immediately  soluble  in  water,  and  which 
did  not  acquire  solubility  even  after  a  few  hours  standing  as  stated 
in  the  official  process.  The  sample  was  therefore  allowed  to  stand 
and  was  tested  at  intervals  to  ascertain  the  length  of  time  that 
