222 
Chemistry  of  a  Cup  of  Coffee. 
Am.  Jour.  Pharm. 
May,  1914. 
produced  by  roasting  is  caffeol,  a  nitrogen-containing  oil,  but  it 
would  be  impossible  to  differentiate  the  quality  of  coffee  upon  an 
analysis  pursued  in  this  direction,  inasmuch  as  the  amount  found 
does  not  exceed  more  than  0.06  per  cent.  It  is  doubtful  whether  it 
has  any  further  value  from  a  dietetic  point  of  view  than  that  sup- 
plied by  its  influence  in  pleasing  the  senses.  When  isolating  caffeine 
from  coffee  infusion  the  solvent  (chloroform)  takes  out  also  a  non- 
crystalline substance  which  unlike  caffeine  is  soluble  in  ether.  This 
substance  has  a  very  strong,  pleasant,  but  somewhat  bitter  flavour 
of  coffee.  The  yield  is  different  according  to  the  quality  of  the 
coffee  examined,  and  it  is  possible  that  this  principle  is  a  determining 
factor  in  the  judgment  given  by  the  expert  coffee  taster.  It  is  a 
product  of  roasting  and  does  not  exist  in  raw  coffee. 
Food  Value  of  Coffee. 
The  infusion  of  coffee  presents  practically  very  little  material 
that  is  of  direct  nourishing  value,  but  by  diminishing  nervous 
fatigue,  by  virtue  chiefly  of  the  caffeine  present,  it  may  increase 
muscular  power.  It  is  not  itself  a  builder  of  tissue.  The  use  of  coffee 
after  dinner,  it  is  of  interest  to  note,  is  justified  in  a  large  number 
of  cases  by  the  fact  of  its  stimulating  effect  upon  the  vital  centres, 
and  it  is  said  to  serve  to  some  extent  as  an  antidote  to  alcohol.  It 
is  commonly  claimed  to  remove  drowsiness ;  as  a  matter  of  fact, 
in  many  subjects  it  produces  drowsiness,  but  this  is  usually  followed 
quickly  by  marked  wakefulness.  The  practice  of  drinking  coffee 
after  a  meal  for  the  sake  of  the  stimulus  which  is  experienced  has 
much  to  be  said  in  its  favour  dietetically.  There  is  no  reason  for  sup- 
posing that  coffee  possesses  any  value  as  a  food.  The  berry  con- 
tains a  quite  important  proportion  of  fatty  substances  (12  per  cent, 
average),  but  these  are  necessarily  excluded  from  the  infusion,  as 
owing  to  their  insolubility  they  remain  in  the  "  grounds." 
According  to  our  analyses  again  the  protein  contents  of  a  cup 
of  coffee  are  small,  approximating  to  1.25  per  cent,  of  the  coffee 
extracted.  This  amount  can  have  little  dietetic  significance.  There 
is  also  a  trifling  quantity  of  dextrin  and  sugar  present  besides  traces 
of  alcohol,  which  again  can  possess  no  importance  from  a  physio- 
logical point  of  view. — The  Lancet,  Nov.  29,  1913,  pp.  1 563-1 565. 
