554  Enzymes  and  Their  Importance. 
longer  assimilates  the  carbonic  acid  of  the  air  with  the  same  inten- 
sity. They  participate  normally  in  the  work  of  fertilization  and  of 
the  formation  of  the  seeds,  in  the  course  of  which  they  are  partially 
consumed. 
THE  ENZYMES  AND  THEIR  IMPORTANCE  IN 
PHARMACOGNOSY.1 
By  A.  Tschirch,  Berne. 
In  his  opening  remarks  Professor  Tschirch  recalled  the  fact  that 
in  an  address  entitled  "  The  Future  of  Pharmacognosy,"  delivered  in 
London  on  the  occasion  of  the  presentation  of  the  Hanbury  Medal 
to  him  (see  C.  &  D.,  1909,  IL,  548),  he  had  considered  it  probable 
that  the  interest  taken  in  the  numerous  synthetic  remedies  would 
be  followed  by  "  a  return  to  drugs."  This  has  taken  place  sooner 
than  he  expected,  for  quite  recently  the  representatives  of  two  im- 
portant chemical-pharmaceutical  factories  informed  him  that  interest 
in  synthetic  drugs  is  declining,  and  that  there  is  a  greater  demand  for 
drugs  and  preparations  of  them,  especially  for  those  which  not  only 
represent  the  active  principles,  but  also  the  whole  of  the  constituents. 
This  fact  draws  once  more  greater  attention  to  that  group  of  remedies 
which  have  been  employed  for  thousands  of  years,  and  the  study  of 
which  is  the  aim  of  pharmacognosy. 
Among  the  fundamental  problems  to  be  solved  is  the  part  played 
by  the  enzymes,  not  only  in  the  synthesis  of  the  active  principles  in 
the  living  plant,  but  also  in  the  transformation  of  the  living  plant 
into  a  drug.  For  long  it  had  been  a  problem  for  chemists  to  explain 
how  the  plant  succeeds  in  executing  at  ordinary  temperature  the 
same  reactions  which  can  be  performed  in  the  laboratory  only  with 
the  aid  of  energetic  agents  (strong  acids  or  bases  and  relatively  high 
temperatures),  and  how  it  is  able  with  the  utmost  facility  and  in  a 
very  short  time  to  perform  syntheses  requiring  a  considerable  amount 
of  energy,  such  as  the  building  up  of  carbohydrates  from  carbonic 
acid  and  water  and  other  photosyntheses.  Formerly  this  ability  was 
ascribed  to  the  "  vitality  "  residing  in  the  living  plant  alone,  and 
representing  its  particular  source  of  energy  for  the  accomplishment 
1  Lecture  delivered  at  a  general  meeting  of  the  Eleventh  International 
Congress  of  Pharmacy,  September  17,  1913.  Reprinted  from  Chemist  and 
Druggist,  Sept.  20,  1913,  pp.  41-43. 
