Am.  Jour.  Pharrr.l 
February,  1903.  J 
Why  Popcorn  Pops. 
77 
discuss,  for  when  a  physician  prescribes  syrup  of  ferrous  iodide  he 
does  not  want  free  iodine  ;  if  he  should,  he  has  the  official  compound 
solution  of  iodine,  which  he  can  make  use  of  and  which  contains  a 
definite  amount  of  free  iodine. 
When  we  consider  the  amount  of  hypophosphorous  acid  consumed 
in  the  form  of  its  various  salts,  present  in  the  much-lauded  com- 
pound syrups  of  hypophosphites,  emulsions  of  cod-liver  oil  with 
hypophosphites,  etc.,  and  which  are  recommended  as  great  nerve 
and  brain  foods,  its  presence,  in  trifling  quantity,  in  the  syrup  of 
ferrous  iodide  should  cause  no  alarm,  nor  should  it  raise  any  objec- 
tions on  the  part  of  the  physician. 
WHY  POPCORN  POPS. 
BY  M.  I.  WlI/BERT, 
Apothecary  at  the  German  Hospital,  Philadelphia. 
Why  popcorn  should  have  the  peculiar  property  of  being  readily 
converted,  from  a  hard,  dense,  flinty  kernel  to  a  deliciously  mealy 
morsel,  by  the  simple  application  of  heat,  is  a  question  that  has 
probably  suggested  itself  to  every  thinking  individual  that  has  ever 
held  a  popper  of  popcorn  over  a  bed  of  hot  coals. 
While  this  question  has,  no  doubt,  been  answered  a  number  of 
times,  I  myself  have  never  found  any  satisfactory  explanation  of  the 
phenomenon,  either  from  books  of  reference  on  general  subjects,  or 
from  inquiries  made  of  a  number  of  individuals  who  might  be 
supposed  to  know. 
A  chance  clipping  from  one  of  the  daily  papers,  in  which  popcorn 
was  recommended  as  a  most  desirable  food-product,  appeared  to 
contain  a  possible  key  to  the  problem. 
The  explanation  given  in  this  particular  clipping  was,  that  "  pop- 
corn being  corn  with  an  excess  of  water  in  it,  and  surrounded  by  a 
tough  envelope  that  retains  the  water,  may  be  heated  over  a  fire 
until  the  contained  moisture  is  converted  into  steam  under  pressure. 
WThen  the  skin  cannot  longer  resist  the  pressure  of  the  steam  within 
it  bursts  and  the  corn  is  fit  to  eat." 
This  appears  to  offer  a  feasible  explanation  of  the  phenomenon, 
with  the  single  exception,  that  instead  of  supposing  each  kernel  to 
be  a  mass  of  corn,  or  cornstarch  and  water,  enveloped  in  a  hard 
