NOTES  ON  IODIDE  OE  POTASSIUM,  ETC. 
367 
I  mention  this  case,  since  it  affords  an  instance  where  neither 
patient  nor  practitioner  were  aware  of  a  change  until  it  declared 
itself  by  its  effects,  and  where  a  difference  (in  favor  of  the  yel- 
low oxide)  was  first  noticed  by  a  person  who,  having  no  theory 
to  prove,  was  perfectly  free  from  all  prejudice. 
I  have  since  then  frequently  tried  in  appropriate  cases  oint- 
ments containing  merely  one  or  the  other  of  the  oxides,  and  the 
result  has  been  uniformly  in  favor  of  the  precipitated  yellow 
oxide  of  mercury. 
Dr.  Attfield  said,  that  not  the  least  important  point  in  any 
proposition  to  introduce  a  new  substance  into  pharmacy  was  the 
character  of  the  name  by  which  it  was  designated.  Mr.  Squire 
had  brought  before  their  notice  two  varieties  of  the  red  oxide  of 
mercury;  one  prepared  by  the  old  method  of  heating  nitrate  of 
mercury,  the  other  by  precipitation  of  solution  of  corrosive  sub- 
limate by  potash.  Mr.  Squire  had  apparently  experienced  some 
difficulty  in  distinguishing  between  these  varieties,  and  had  not 
yet  succeeded  in  stating  the  true  distinction.  The  fact  was  that 
the  old  kind  was  perfectly  free  from  water,  while  that  precipi- 
tated from  solution  contained  twenty  per  cent. ;  the  one  was 
anhydrous  red  oxide,  the  other  hydrated  red  oxide. 
Mr.  Daniel  Hanbury  said  that  the  house  with  which  he  was 
connected  had  many  years  since  prepared  for  a  well-known  prac- 
titioner in  skin  diseases  a  similar  ointment  to  that  now  suggested 
by  Mr.  Balmanno  Squire,  but  the  old  sort  had  been  returned  to. 
— London  Pharmaceutical  Journal,  April  1,  1865. 
NOTES  ON  IODIDE  OF  POTASSIUM,  ETC. 
By  Mr.  William  Huskisson,  Jun. 
The  "  Pharmaceutical  Journal  "  for  October  last  contains  an 
interesting  report  by  Mr.  Clayton,  in  which  he  forms  a  compari- 
son, based  upon  quantitative  and  qualitative  analysis,  between 
the  relative  values  of  English  and  Foreign  Iodides  of  Potassium. 
The  impurities  in  the  commercial  English  iodide  may  be  fairly 
considered  as  accidental.  The  chloride  of  potassium  is  derived 
from  the  American  pearlashes  employed  in  the  process  which, 
