Paraffin  Oil. 
f  Am.  Jour.  Pharm. 
\      April,  1914. 
with  the  product,  non-proprietary  oils  of  high  quality  are  readily 
available  and,  finally,  that  these  non-proprietary  products  can  be 
sold  to  the  patient  at  a  very  much  lower  figure  than  can  the  pro- 
prietary article  and  still  yield  the  retail  druggist  a  more  satisfactory 
profit. 
As  intimated  above,  the  products  that  are  available  at  the  present 
time  are  many,  or  at  least  appear  to  be  numerous  because  of  the 
varied  trade  names  under  which  they  are  offered.  On  studying  the 
nature  of  these  products,  however,  it  appears  that  there  is  no  very 
great  difficulty  in  establishing  certain,  at  times  perhaps  arbitrary, 
lines  of  demarcation  between  them  and  identifying  them  as  belong- 
ing to  one  or  the  other  class  of  commercially  available  oils  readily 
obtainable  by  any  pharmacist. 
The  bulk  of  the  available  supply  of  heavy  mineral  oil  comes  from 
two  sources  and  the  products  differ  materially  in  chemical  composi- 
tion. The  American  oil  is  obtained  from  paraffin  base  petroleum  and 
consists  essentially  of  hydrocarbons  of  the  methane  series  having  the 
general  formula  CnH2n  -f-  2. 
The  so-called  Russian  Oil,  obtained  largely,  if  not  entirely,  from 
the  oil  wells  in  the  Baku  district,  consists  chiefly  of  monocylic  poly- 
methylenes  or  napthenes,  having  the  general  formula  CnH2n. 
These  latter  products  have  been  described  as  hydrated  aromatic 
hydrocarbons  and  while  they  behave  with  reagents  very  much  in  the 
same  way  as  do  the  hydrocarbons  of  the  methane  series,  they  are 
more  readily  purified  and  generally  occur  in  commerce  as  water 
white  oils  that  are  quite  free  from  fluorescence  or  odor.  The  Amer- 
ican paraffin  or  methane  oils  usually  have  a  distinct  color  and  are 
seldom  quite  free  from  fluorescence  or  a  peculiar  dichroic  effect 
that  is  particularly  noticeable  when  the  preparation  is  viewed  by 
reflected  light.  Apart  from  the  appearance,  however,  there  is  no 
evidence  that  the  two  products  differ  in  their  effect  on  the  animal 
organism  and  one  has  perhaps  as  many  advocates  and  users  as  the 
other. 
The  density  of  the  commercially  available  products  also  varies 
and  the  fact  that  it  is  proposed  to  extend  the  present  U.  S.  P.  limits 
of  specific  gravity,  0.870  to  0.940  at  25  °,  to  read  0.845  to  0.940  at 
25 0  clearly  indicates  that  the  members  of  the  present  Committee  of 
Revision  are  themselves  not  convinced  as  to  the  properties  that 
should  be  inherent  in  a  mineral  oil  for  medicinal  use. 
The  paraffin  oils  official  in  the  Pharmacopoeias  of  the  Continent 
