Am.  Jour.  Pharm. 
April,  1889. 
Glycerinum  Aeidi  Gallici. 
183 
solution.  The  glycerin,  acid,  gallic,  used  had  been  very  recently 
prepared  and  was  of  a  very  faintly  brownish  tint. 
I  obtained  samples  of  glycerin,  acid,  gallic,  from  different  pharma- 
cies and  treated  them  as  follows : — To  4  drachms  of  each  sample  I 
added  4  ounces  of  distilled  water,  and  exposed  the  mixture  to  a  tem- 
perature of  32°  F.  Even  after  the  lapse  of  two  or  three  hours  no  crys- 
tallization had  taken  place.  Repeating  the  experiment  with  various 
samples  of  glycerin,  acid,  gallic,  which  I  had  recently  prepared  from 
different  samples  of  gallic  acid,  crystallization  began  almost  imme- 
diately. All  these  samples  were  made  with  only  just  sufficient 
heat  to  dissolve  the  gallic  acid  by  placing  them  in  a  water-bath.  A 
portion  of  a  freshly  prepared  sample  of  glycerin,  acid,  gallic,  was 
heated  to  340°  F.  for  about  5  minutes.  Bubbles  of  carbon  dioxide 
were  given  off,  and  the  gallic  acid  was  evidently  changing  into  pyro- 
gallol.  On  using  this  overheated  sample  to  make  the  mixture  there 
was  only  a  very  slight  separation  of  crystals  even  after  exposure  to  a 
temperature  of  20°  F.  This  I  account  for  by  the  partial  change  of 
the  gallic  acid  into  pyrogallol,  which  is  freely  soluble  in  water.  I 
think  it  is  probable  that  a  change  similar  to  that  produced  by  over- 
heating takes  place  in  this  preparation  after  long  keeping,  and  that 
this  accounts  for  the  fact  that  separation  of  crystals  only  took  place 
when  freshly  prepared  samples  were  used.  It  is,  of  course,  possible 
that  too  great  heat  was  used  in  making  some  of  the  commercial  sam- 
ples I  obtained. 
I  observe  Squire  states  that  in  the  case  of  glycerin,  acid,  gallic, 
part  of  the  acid  separates  on  cooling  and  remains  undissolved.  This, 
however,  I  cannot  confirm.  I  have  prepared  various  samples  from 
different  acids,  and  glycerin  of  B.  P.  specific  gravity,  using  as  low  a 
heat  as  possible  to  effect  solution,  and  even  at  a  temperature  below 
freezing  no  separation  took  place.  It  is,  however,  a  saturated  solu- 
tion, and  if  made  stronger  the  acid  is  sure  to  crystallize. — Phar.  Jour, 
and  Trans.,  March  16,  p.  755. 
Lactic  Aci«l  in  Diarrhoea.— Sezary  and  Aune  (Lyon  Med.)  have  suc- 
cessfully used  lactic  acid  against  the  diarrhoea  of  tuberculous  patients,  the 
stools  be  coming  natural  in  a  few  days.  They  commenced  with  2  gm  in  a 
glassful  of  water,  given  frequently  in  small  doses  during  24  hours;  if  neces- 
sary the  quantity  is  increased  to  6  or  8  gm.  a  day,  and  a  little  chlorodyne 
may  be  added. 
