102 
PRACTICAL  NOTES  ON  PHARMACY. 
in  the  latter  the  active  matter,  and  to  exclude  the  above  men- 
tioned substances. 
The  consistence  of  syrups  is  a  matter  frequently  too  much  neg- 
lected. The  Pharmacopoeia  directs  them  to  have  the  specific  grav- 
ity 1*261  when  boiling,  and  1319  when  cold.  This  may  be  read- 
ily ascertained  by  an  hydrometer,*  the  specific  gravity  bottle  or, 
by  observing  the  boiling  point  which,  for  syrup  of  the  proper  den- 
sity, is  221°  F. 
Temperature  exercises  an  important  influence  on  syrups  ;  fre- 
quently a  syrup  which  during  the  summer  season  is  of  the  proper 
consistence,  is  rendered  by  the  diminished  temperature  of  winter  so 
dense  that  the  sugar  begins  to  crystallize,  and,  if  the  crystals  are 
not  removed,  the  crystallization  will  proceed  until  the  syrup  has 
not  enough  sugar  left  to  preserve  it,  and  fermentation  sets  in. 
The  preservation  of  these  medicines  is  attended  with  difficulty, 
unless  indeed  some  foreign  preservative  agent  be  added.  If,  however, 
the  fermentable  substances  before  mentioned  be  excluded,  and  the 
syrup  be  of  full  saccharine  strength  and  bottled,  it  will  require  no 
other  precaution  than  that  of  guarding  against  too  sudden  or  ex- 
treme changes  of  temperature,  and  unnecessary  exposure  to  the 
atmosphere. 
The  practice  of  adding  alcohol,  or  of  not  evaporating  all  of  it 
from  a  tincture  of  which  the  syrup  is  sometimes  made,  is  therapeu- 
tically so  objectionable,  especially,  when  the  syrup  is  used  in  cases 
attended  with  inflammation,  that  it  should  never  be  done.  Hoff- 
man's anodyne  is  not  liable  to  the  same  objection,  and  as  the 
quantity  necessary  is  small  (1  part  by  measure  to  75  of  syrup)  it 
might  sometimes  be  added  advantageously. 
But  all  syrups  may  be  effectually  preserved  by  introducing  them 
while  hot  into  small  bottles,  corking  securely  and  sealing  ;  they 
should  then  be  kept  standing  in  a  cool  place.  The  bottles  should 
be  very  nearly  full  otherwise  the  air  enclosed  would  probably  be 
sufficient  to  start  fermentation.  It  is  worthy  of  note  also,  that 
the  exposure  of  much  surface  to  even  a  small  portion  of  air,  is  like- 
ly to  start  fermentation  ;  consequently  the  practice  of  laying  bot- 
*  Hydrometers  are  sold  by  Messrs.  Haskell,  Merrick  &  Bull,  of  New  York, 
which  give  the  actual  sp.  gr.  in  figures.  They  are  in  cases  of  three,  which 
also  contains  ajar  for  testing  liquids  and  a  chemical  thermometer.  The  in- 
struments are  very  accurate. 
