THE  AMERICAN 
JOURNAL  OF  PHARMACY. 
MAY,  1882. 
STRENGTH  OF  ALCOHOLIC  MENSTRUA,  REFERRED 
TO  COMMERCIAL  ALCOHOL  AS  A  STANDARD. 
By  a.  B.  Lyons,  A.M.,  M.D.,  Detroit,  Mich. 
Most  of  the  existing  tables  which  give  the  alcoholic  strength  of  dis- 
tilled spirits  adopt  absolute  alcohol  as  the  basis  for  all  computations. 
Many  calculations  in  practice,  however,  would  be  greatly  simplified 
by  adopting  the  stronger  alcohol  of  the  pharmacopoeia,  which  coincides 
nearly  with  commercial  alcohol,  as  a  standard.  Among  the  problems 
of  most  frequent  occurrence  in  practice  are  the  estimation  of  the  com- 
mercial value  of  spirit  of  a  given  density,  or  the  preparation  from 
commercial  alcohol  of  a  menstruum  which  shall  contain  a  given  pro- 
portion of  alcohol,  by  volume  or  by  weight. 
While  there  are  many  pharmacists  who  will  adopt  at  once  the 
practice  of  weighing  alcohol,  when  the  pharmacopoeia  so  directs,  there 
are  many  others  who  will  find  it  still  convenient  to  follow  their  accus- 
tomed practice  of  measuring  it,  and  some  even,  I  have  no  doubt,  will 
go  so  far  as  to  translate  for  practical  use  the  weights  of  the  new 
formulas  into  volumes.  Partly  to  accommodate  such,  but  chiefly 
because  alcohol  is  still  bought  and  sold  by  the  gallon,  and  not  by  the 
pound,  I  have  adopted  volume  rather  than  weight  as  the  central  idea 
of  the  accompanying  tables.  Hence,  for  commercial  alcothol  I  have 
used  the  expression  94  per  cent,  alcohol,  even  where  weight  rather 
than  volume  is  immediately  under  consideration.  The  expression 
commercial  alcohol  is  open  to  objection,  inasmuch  as  the  commercial 
article  is  not  of  uniform  strength. 
The  use  of  the  tables  is  obvious  without  elaborate  explanation. 
A  spirit  of  any  desired  strength  may  be  made,  of  course,  by  putting 
into  a  graduated  receiver  the  required  amount  of  alcohol  (of  commerce) 
and  adding  water  to  make  up  the  desired  volume.  Where  accuracy 
is  not  aimed  at  this  plan  commends  itself  by  its  simplicity,  but  unless 
time  is  given  for  the  mixture  to  cool,  the  resulting  spirit  will  be  too 
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