AFebmaiy5b9i3m'}     R^sins  and  Relations  to  Ter  penes.  53 
THE  RESINS  AND  THEIR  CHEMICAL  RELATIONS  TO 
THE  TERPENES.1 
By  George  B.  Frankforter.2 
The  closing  years  of  the  eighteenth  and  the  beginning  of  the 
nineteenth  centuries  found  chemists  engaged  in  the  study  of  chem- 
ical problems  related  to  both  plant  and  animal  life.  Organic 
chemistry  during  this  early  chemical  epoch  was  exactly  what  its 
name  implied,  a  study  of  those  substances  which  are  produced 
through  life  processes,  either  plant  or  animal.  During  this  early 
epoch,  the  problems  in  plant  chemistry  were  more  inviting  to  the 
chemist  than  those  in  animal  life,  first,  because  the  compounds 
appeared  to  be  simpler  substances  and,  second,  because  they  crystal- 
lized more  readily  and  were  therefore  more  readily  obtained  in 
pure  form.  As  a  result  of  these  characteristics,  early  organic 
chemistry  was  largely  confined  to  plant  life,  consisting,  however, 
of  little  more  than  the  simple  preparation  of  the  substances 
themselves. 
Scheele  was  the  first  to  point  out  that  the  plant  and  animal 
world  is  made  up  of  definite  compounds,  just  as  is  the  inorganic 
world.  He  proved  the  assertion  by  isolating  a  number  of  organic 
substances,  among  them  tartaric,  citric,  malic  and  uric  acids.  He 
even  went  so  far  in  his  study  of  the  organic  compounds  as  to 
suggest  what  the  modern  physiological  chemist  calls  metabolism, 
as  a  means  of  explaining  certain  physiological  processes.  Owing, 
however,  to  the  extreme  difficulty  in  obtaining  physiological  com- 
pounds in  crystalline  form,  Scheele  devoted  much  time  to  phyto- 
chemistry,  discovering  more  than  a  score  of  important  plant  com- 
pounds besides  those  mentioned  above.  Other  men  followed  in 
his  footsteps  and  by  the  beginning  of  the  last  century  many  of 
the  important  plant  compounds  had  been  isolated. 
At  the  very  beginning  of  what  may  be  justly  called  the 
renaissance  in  organic  chemistry,  Marggraf  (1745-79)  completed 
1  Reprinted  from  Science,  N.  S.,  Vol.  XXXVI,  No.  922,  Pages  257-263, 
August  30,  1912. 
2  A  pait  of  the  address  of  the  vice-president  and  chairman  of  Section  C, 
American  Association  for  the  Advancement  of  Science,  Washington, 
December,  191 1. 
