84 
VARIETIES. 
sure,  and  without  straining  evaporate  to  a  proper  consistence.  One  grain  is 
about  equal  to  three  of  the  powder. — Pharm.  Jour.  September,  1852. 
Hospital  Sulphate  of  Quinine. — Mr.  Edward  Herring  has  introduced  a 
preparation  under  this  name,  consisting  of  disulphate  of  quinine  only 
partially  purified.  In  its  medicinal  properties  it  is  said  to  differ  but  little 
from  the  ordinary  disulphate.  It  has  a  brownish  color,  and  of  course  is 
not  admissable  as  a  substitute  for  disulphate  of  quinine  in  general  dis- 
pensing, but  it  has  been  tried  in  hospitals  and  dispensaries,  and  by  some 
medical  men  who  dispense  their  own  medicines.  The  final  purification 
and  decolorization  of  the  salt  being  attended  with  some  expense,  the 
manufacturer  is  enabled  to  offer  it  in  a  partially  purified  state  at  a  con- 
siderable reduction  from  the  prices  at  which  it  can  be  sold  when  purified 
in  the  usual  way.  The  amount  of  impurity  must  be  ascertained  before 
its  real  value  can  be  estimated.  It  may  be  a  question  whether  the  recog- 
nition of  a  preparation  so  imperfectly  purified  might  not  open  the  door  to 
some  abuse. — Lond.  Pharm.  Journ.,  Nov.  1852. 
Felt  and  Chamois  Leather  Plasters. — Messrs.  Wright  and  Ewing  have 
introduced  a  material  which  is  likely  to  be  valuable  to  patients  requiring 
plasters  for  bad  sores.  It  may  also  be  useful  for  other  purposes.  It  con- 
sists of  a  felt,  more  soft  in  its  texture  than  that  which  is  used  for  hats, 
and  is  covered  on  one  or  both  sides  with  chamois  leather.  The  plaster 
is  either  spread  on  the  leather  or  on  the  felt.  In  either  case,  it  appears 
to  be  an  application  likely  to  prove  serviceable.  It  may  be  used  for  re- 
moving pressure  from  any  particular  spot,  by  cutting  a  hole  in  the 
plaster  at  the  part  affected. — Ibid. 
On  Litmus.  By  Dr.  J.  Muller,  apothecary  at  Berlin. — According  to 
Dr.  Miilier,  the  inferior  sorts  only  of  litmus  contain  a  mechanical  admix- 
ture of  indigo.  Whilst  moist,  the  litmus  is  introduced  into  a  swing-machine 
[Schwungmaschine]  containing  finely  powdered  indigo,  and  worked  until 
it  has  assumed  an  uniform  color.  But  neither  Prussian  blue  nor  cobalt 
is  employed. 
In  the  manufacture  of  litmus  all  kinds  of  lichens,  even  indigenous  sorts, 
are  employed ;  but  the  best  quality  is  prepared  in  Holland  exclusively 
from  Roccella  tinctoria.  Inferior  sorts,  however,  are  made  from  species  of 
Variolaria,  Lecanora,  and  Parmelia.  These  are  finely  ground  and  placed 
in  contact  with  nitrogenous  substances,  especially  urine,  at  a  certain  tem- 
perature. The  first  product  is  a  red  coloring  matter,  which  is  formed 
slowly,  if  sufficient  attention  be  not  paid  to  the  process,  and  equally  high 
temperature  maintained.  As  soon  as  this  stage  has  been  attained,  some 
potashes  are  added,  not  American,  Russian  or  Illyrian,  but  a  German  sort, 
which  contains  a  peculiar  constituent  and  cannot  be  manufactured  in 
Holland.  Upon  this  constituent,  and  the  addition  of  Carrara  marble,  rests 
chiefly  the  secret  of  obtaining  a  good  litmus. — Ibid,  from  Archiv.  de  Pharm. 
