88 
Expansion  of  Urine. 
(Am.  Jour.  Pharm. 
{       Feb.,  1884. 
25  to  35  per  cent,  larger,  and  the  time  consumed  one  to  two  hours 
less. 
In  concluding  this  paper  I  would  state  that  I  have  endeavored  to 
get  all  the  information  it  was  possible  for  me  to  obtain  ;  also,  that  if 
all  the  "  light  oil "  or  "  light  ring  "  is  like  that  examined  by  me,  there 
should  be  no  difficulty  in  giving  it  a  name.  The  two  samples  of  oil 
examined,  of  which  one  was  a  year  and  the  other  but  a  few  days  old, 
contained  no  terpene,  and  the  result  agrees  with  Mr.  Pettigrew's  obser- 
vation, that  oil  of  birch  is  neaily  pure  salicylate  of  methyl.  The 
"  light  oil,"  so  called  by  distillers,  is  shown  to  be  water  and  oil ;  if  the 
chips  and  dirt  were  removed  from  the  distillate  the  oil  and  water 
would  readily  separate. 
NOTES  ON  THE  EXPANSION  OF  URINE  BY  INCREASE 
OF  TEMPERATURE. 
By  A.  B.  Lyons,  M.D.,  Detroit,  Mich. 
In  order  that  an  observation  of  the  specific  gravity  of  urine  shall 
be  of  any  value,  either  the  experiment  must  be  made  always  at  the 
same  temperature,  or  else,  the  actual  temperature  being  noted,  an  arbi- 
trary correction  must  be  applied.  In  clinical  practice  the  first  alterna- 
tive involves  difficulties  not  easily  surmounted,  and  most  physicians 
would  prefer  to  adopt  the  second.  Unfortunately,  however,  their  text- 
books are  either  silent  altogether  as  regards  the  amount  of  the  correc- 
tion, or  else  the  positive  statements  made  by  one  authority  contradict 
those  of  another.  Thus  Neubauer  and  Yogel  state  that  according  to 
the  observations  of  Siemon  the  specific  gravity  of  a  urine  which  at 
12°C.  was  1-021,  at  15°C.  sank  to  1-020,  and  at  18°C.  to  1-019,  so 
that  a  difference  of  temperature  of  3°C  corresponds  to  about  one 
degree  of  the  urinometer.  Beneke,  they  add,  arrived  at  the  same 
results.  Witthaus  probably  quotes  the  same  authority  when  he  says 
(Manual  of  Chemistry,  p.  5) :  "In  a  complex  fluid  like  the  urine  a 
correction  for  temperature  can  be  made  roughly  by  allowing  1  °  of  spe- 
cific gravity  for  each  3°C.  (5*4°  Fahr.)  of  variation  in  temperature." 
Dr.  Squibb,  in  the  September  "  Ephemeris,"  makes  a  similar  state- 
ment. Dr.  Golding  Bird,  on  the  other  hand,  makes  a  correction  of 
only  about  one-half  this  amount,  i.  e.,  between  60°  and  71  °F.,  of  one 
degree  of  the  urinometer,  and  between  71°  and  81°,  of  the  same 
