434 
Pill  Coating. 
f  Am.  Jour.  Pharm. 
(      Sept.,  1879. 
It  seems  hardly  necessary  to  speak  of  resinous  coatings,  as  apart 
from  the  insolubility  of  the  resin  the  same  dry,  hard  pill  is  needed  as  in 
the  case  of  sugar.  Dipping  in  gum,  or  sugar  solution,  and  then  rolling 
in  either  powdered  starch,  slippery  elm,  French  chalk,  etc.,  fails  to  pro- 
duce a  coating  which  I  would  take  much  pride  in  ;  the  pill  dries  slowly, 
and  when  dispensed  in  an  excess  of  powder  without  drying,  complaints 
are  raised  that  the  coating  adheres  to  the  fingers  or  to  the  patient's 
mouth,  and  that  the  pill  tastes  very  bad.  When  thoroughly  dry,  I  find 
these  coatings  very  insoluble,  more  so  than  at  first  I  would  have 
thought  possible. 
A  mass  for  coating,  composed  of  flaxseed,  Irish  moss  and  sugar  (as 
recommended  in  the  "  Druggists'  Circular  ")  was  tried,  but  was  found 
to  harden  slowly  and  to  mould  easily,  but  to  be  very  soluble.  Gelatin 
has  given  me  the  best  satisfaction,  and  more  closely  approaches,  I  think, 
what  we  want  in  a  quick  yet  efficient  coating,  as  pills  can  be  coated 
while  soft,  the  coating  hardens  quickly,  is  elegant  in  appearance  and 
does  not  require  much  skill  in  applying.  Among  the  disadvantages  in 
its  use  should  be  mentioned  insolubility  of  coating,  if  the  gelatin  has 
not  been  carefully  selected  ;  moulding,  if  the  coating  is  too  thick  ;  stick 
iness  of  coating,  from  carelessness  about  concentration  of  solution  ; 
the  time  required  and  the  trouble  in  handling  the  pills  on  needles  ;  ina- 
bility to  keep  the  mass  ready  for  use,  owing  to  decomposition,  and  the 
injury  caused  by  successive  heatings. 
In  regard  to  quality  of  gelatin,  I  find  from  such  authorities  as  are 
within  my  reach,  that  Messrs.  Cox,  of  Gorgie,  near  Edinburgh,  make, 
through  their  patented  processes,  as  pure  a  gelatin  as  is  in  the  British 
market,  with  perhaps  the  exception  of  Mr.  Mackay's,  which  is  only 
made  in  small  quantities,  and  that  the  French  gelatins  are  fine  in  appear- 
ance but  generally  of  inferior  quality,  and  said  to  be  largely  manufac- 
tured from  the  immense  numbers  of  rats  caught  in  the  sewers  and 
abbattoirs  (or  public  slaughter  houses)  of  Paris,  etc. — (Chambers' 
Encyclopaedia).  French  gelatin  is,  to  a  certain  extent,  made  from 
bones,  by  removing  earthy  salts  with  diluted  hydrochloric  acid  and  gela- 
tin with  hot  water — (  Appleton's  Cyclopaedia).  Bone  gelatin  is 
inferior  in  digestibility,  etc. — ( Tomlinson's  Cyclopaedia).  Ure's 
Diet.  Arts,  Manuf 'rs,  etc.,  page  626,  speaks  of  Nelson's  gelatin  as 
good,  but  of  Cox's  as  the  best.    From  these  authorities,  and  from 
