Am.  Jour.  Pharm.j 
March,  19 17  J 
Phytochemical  Research. 
109 
and  is  soluble  in  all  the  ordinary  organic  solvents.  When  heated  al 
60-700  C.  with  metallic  sodium  and  barium  peroxide,  it  is  con- 
verted quantitatively  into  normal  isoprene-caoutchouc,  whereas 
under  similar  conditions  isoprene  gives  an  abnormal  caoutchouc.  It 
has  thus  been  considered  by  one  of  the  investigators21  that  this  poly- 
merization of  chemically  pure  /3-myrcene  may  possibly  represent 
the  only  synthesis  of  natural  caoutchouc,  that  is,  of  a  substance  per- 
fectly identical  with  natural  Para  caoutchouc,  both  in  the  general 
structure  of  its  nucleus  and  also  in  the  position  of  the  methyl  groups 
and  double  linkings  of  the  molecule.  In  this  connection  it  has  been 
remarked  that  there  is  every  reason  to  believe  that  tropical  plants 
synthesize  caoutchouc  by  means  of  /?-myrcene  or  myrcene-like  hydro- 
carbons or  their  dimerides,  and  not  by  the  polymerization  of  isoprene 
The  view  has  furthermore  been  expressed  that,  inasmuch  as  com- 
pounds with  an  atomic  grouping  like  that  of  myrcene,  such  as 
geraniol,  linalool,  nerol,  etc.,  are  of  frequent  occurrence  in  plants, 
the  simple  dehydration  of  these  unsaturated  alcohols  would  lead 
immediately  to  the  corresponding  myrcenes. 
With  consideration  of  the  observations  to  which  I  have  just 
referred,  it  would  appear  to  be  of  some  interest  to  ascertain  whether 
myrcene  or  an  analogous  hydrocarbon  is  contained  in  plants  yield- 
ing rubber.  If  fresh  material  were  available,  experiments  in  this 
direction  could  very  easily  be  conducted. 
The  few  examples  that  have  been  given  of  recent  phytochemical 
investigations,  although  fragmentary  in  character,  may  serve  in  some 
measure  to  illustrate  their  development  and  scope.  It  has  naturally 
not  been  possible  in  the  short  space  of  time  to  give  adequate  con- 
sideration to  the  large  number  of  important  researches  which  in 
recent  years  have  been  conducted  by  various  other  workers  in  this 
field  of  science.  Among  these  there  may  specially  be  noted  the 
contributions  to  the  knowledge  of  chlorophyll  and  the  coloring 
matter  of  flowers,  and  also  those  pertaining  to  the  compounds  which 
impart  to  flowers  their  fragrance.  On  the  other  hand  it  will  doubt- 
less be  conceded  that  no  very  extended  account  of  phytochemical  in- 
vestigations would  be  necessary  in  order  to  demonstrate  their  utility, 
for  an  enumeration  of  even  a  few  of  the  organic  plant  constituents 
which  have  long  been  known  and  largely  used,  either  in  medicine  or 
the  arts,  would  alone  afford  sufficient  evidence  of  the  lasting  benefit 
which  such  investigations  may  confer  on  mankind. 
21  Ostromyslenski,  ibid.,  pp.  1941-1947. 
