Am  j!n1er*i8P84arin' }        Microscopical  Examination  of  Malt.  309 
two-thirds  the  length  of  the  grain,  it  is  stopped  completely  by  kiln- 
drying.  This  is  done  in  a  large  room  with  a  brick  or  tile  floor  which 
is  heated  by  steam.  Here  the  barley  is  finished  by  being  perfectly 
dried,  and  this  product  constitutes  the  officinal  malt. 
Much  depends  upon  the  temperature  used  in  this  last  operation ;  if 
the  heat  is  sufficient  to  scorch  it,  it  is  ruined  as  malt,  but  is  used  for 
coloring  porter,  etc.  When  the  temperature  varies  from  90°  to  100° 
F.,  pale  malt  results ;  this  is  the  kind  required  by  the  Pharmacopoeia. 
The  barley  grain  is  elliptical  in  shape ;  its  principal  part  is  the  fari- 
naceous matter,  as  the  embryo  occupies  but  a  small  indenture  at  one 
end  and  on  the  outside.  On  the  opposite  side  from  the  embryo,  run- 
ning lengthwise,  is  a  gradually  broadening  groove.  Closely  adhering 
to  the  endosperm  is  the  pericarp,  and  outside  of  this  is  the  so-called 
husk.  Both  the  pericarp  and  the  husk  are  smooth  and  continuous 
over  the  embryo,  and  terminate  in  the  groove. 
A  transverse  section  through  the  barley  grain  shows  the  thin -walled 
parenchyma  radiating  from  the  groove,  and  on  the  outer  edge  two  or 
three  rows  of  gluten  cells :  beyond  these  are  the  tabulated  cells  of  the 
husk,  in  which  is  deposited  a  large  amount  of  silica :  between  these  is 
seen  a  brown  line  of  indefinite  structure,  which  forms  the  pericarp. 
The  gluten  cells  extend  around  the  grain,  but  as  the  pericarp  descends 
into  the  groove  they  are  obliterated. 
The  simple  theory  of  malting  is  that  in  the  presence  of  moisture 
absorbed  during  the  steeping  operation,  and  with  a  certain  amount  of 
heat,  the  diastase  which  is  developed  during  germination  converts  the 
starch  into  a  fermentable  sugar  called  maltose.  As  the  malting  pro- 
cess advances,  the  proportion  of  starch  diminishes,  while  that  of  the 
sugar  increases.  It  was  thought  that  it  might  be  possible  to  study 
this  change  of  starch  into  sugar  microscopically,  not  expecting  that  the 
sugar  could  be  distinguished  under  the  microscope,  but  that  the  disap- 
pearance of  the  starch  granules  could  be  gradually  traced,  and  the 
indications  thus  gained  would  be  of  practical  service  by  definitely  set- 
tling the  period  of  time  necessary  for  the  transformation  of  the  starch. 
With  the  hope  of  determining  when  there  was  the  greatest  change 
in  number  and  appearance  of  the  starch  granules,  transverse  sections 
of  the  barley  grain  have  been  made,  and  also  of  the  barley  in  its  dif- 
ferent stages  of  malting,  from  the  steeped  down  through  the  series, 
even  including  that  which  had  been  exposed  ten  days.  The  following 
results  have  been  obtained :  The  starch  granules  of  the  barley  vary  in 
