NOTES  ON  PLASMA. 
557 
My  experience,  therefore,  leads  me  to  suggest  but  little 
change  in  my  original  instructions,  which  were  as  simple  as 
could  well  be — viz.  :  — "  Take  of  starch-powder  70  grs.,  glycer- 
ine 1  fl.  oz. ;  mix  the  ingredients  cold,  and  heat  to  240°,  con- 
stantly stirring."  All  I  would  add  to  that  is,  if  the  batch  be 
large,  say  10  lb.  or  20  lb.,  it  is  better  to  escape  the  dreary  task 
of  constantly  stirring  so  large  a  mass,  whilst  it  is  being  gradually 
heated  to  240°  (which  must  be  done  if  the  starch  be  added.) 
This  can  be  accomplished  by  mixing  the  starch  with  about  one- 
twelfth  of  the  glycerine,  placing  the  remainder  on  the  fire,  and, 
when  this  has  become  heated  to  260°,  (which  will  involve  no 
special  attention),  mixing  all  together  and  stirring  till  com- 
plete. I  venture  then  to  repeat  my  opinion  that  plasma,  care- 
fully made,  is  a  very  elegant  and  useful  material,  possessing 
features  of  undoubted  advantage  over  the  fats  commonly  em- 
ployed for  ointments,  and  is  not  liable  to  any  serious  incon- 
veniences. 
I  wish  now  more  particularly  to  refer  to  some  of  Dr.  Red- 
wood's remarks  contained  in  his  paper,  "  On  the  Construction  of 
a  Pharmacopoeia"  (April  5,  1865),  and  more  especially  to  the 
nomenclature  by  which  he  proposes  to  designate  this  solid 
preparation  of  mine  and  certain  other  classes  of  fluid  com- 
pounds of  glycerine.  He  introduces  the  matter  by  a  kindly 
and  favorable  mention  of  plasma.  He  says  (vol.  vi.,  2d  series, 
p.  572  :— 
In  external  applications,  also,  some  improvement  has  been 
made.  The  old  form  of  ointment  has  often  been  referred  to  as 
one  calling  for  improvement,  for  what  can  be  more  offensive 
than  a  rancid  unguent  smeared  over  the  skin  ?  The  so-called 
*  plasma,'  which  was  introduced  by  Mr.  Schacht,  of  Clifton,  in 
1858,  is  certainly  a  great  improvement  in  elegance  and  the  ab- 
sence of  repulsiveness  upon  the  forms  previously  used  for  simi- 
lar purposes.  This  plasma,  which  is  a  solution  of  starch  in 
glycerine,  has  now  been  in  use  for  several  years,  and  there  ap* 
pears  to  be  but  one  objection  to  it,  which  is  that,  if  exposed  to 
the  air,  it  absorbs  moisture,  and  is  then  liable  to  become  mouldy. 
But  it  has   several  recommendations,  and  it  will  probably 
