430  Bitter  Substance  of  Hops.  {^4^35*"* 
which  can  be  isolated  by  treatment  with  a  weak  soda-lye ;  this  sub- 
stance, like  the  crystallized  acid,  is  soluble  in  alkalies,  and  can  be  pre- 
cipitated from  an  alkaline  solution  by  an  acid.  Old  hops  furnish  far 
less  erystallizable  acid  than  new  hops ;  from  some  samples  I  have  been 
able  to  obtain  only  a  few  crystals ;  the  remainder  had  been  trans- 
formed into  the  resinous  modification. 
If  pure  hop-bitter  acid  be  pulverized  and  exposed  to  the  atmosphere 
it  soon  turns  yellow  and  the  surface  assumes  a  resinous  consistency. 
At  the  same  time,  a  more  pronounced  odor  of  fatty  acids  and  alde- 
hydes is  apparent.  Still  more  rapidly  will  this  oxidation  occur  if  a 
thin  layer  of  an  alcoholic  solution  of  the  acid  is  allowed  to  evaporate 
in  the  air.  On  the  other  hand,  we  can  allow  hop  oil  to  stand  for  days 
without  its  odor  being  perceptibly  changed ;  it  appears  to  me  more  than 
probable  that  the  peculiar  smell  of  old  hops  is  due  far  more  to  the 
oxidation  of  the  bitter  substance  than  to  the  oxidation  of  oil. 
Hop-bitter  acid  appears  to  possess  the  character  of  an  aldehyde  and 
of  a  weak  acid ;  for  the  present  I  am  not  in  a  position  to  state  its  con- 
stituents more  clearly.  Most  of  the  oxidizing  processes  have  an  ener- 
getic effect  on  it,  forming  also  considerble  quantities  of  valerianic 
acid. 
The  question  as  to  whether  the  hop  owes  chiefly  to  this  acid  and  its 
resinous  modifications  the  property  of  imparting  a  pronounced  bitter 
flavor  to  a  solution,  I  must  for  the  present  leave  unanswered.  The 
acid  and  its  isomer  are  both  insoluble  in  water ;  they  are,  on  the  other 
hand,  very  readily  dissolved  in  hop  oil ;  they  also  furnish  a  tolerably 
bitter  solution,  if  boiled  for  a-  long  time  in  water,  probably  on  account 
of  their  gradual  decomposition.  I  will  not  for  the  present  go  further 
into  the  subject,  as  I  hope  soon  to  be  in  a  position  to  give  more  defi- 
nite information. — Phar.  Jour,  and  Tram.,  June  14, 1884,  p.  1008. 
Cider  as  a  Preventive  of  Stone,  is  attracting  attention  in  France. 
Dr.  Dennis  Dumont  examined  the  records  of  the  Caen  Hospital,  and  found 
that  in  fifty-nine  years  only  four  cases  of  stone  in  the  bladder  were  admitted. 
He  attributes  this  immunity  to  the  fact  that  the  residents  of  the  country 
are  cider  drinkers,  which  beverage  is  a  decided  diuretic.  Enquiry  showed 
that  the  residents  of  other  cider-drinking  districts  enjoy  the  same  immunity 
from  stone. —  Weekly  Med.  Review. 
