THE  AMERICAN 
JOURNAL  OF  PHARMACY 
JUNE,  i go i. 
RECENT   DEVELOPMENTS   IN   THE   STUDY   OF  THE 
RELATIONSHIP  BETWEEN  CHEMICAL  CONSTI- 
TUTION AND  PHYSIOLOGICAL  ACTION 
OF  ORGANIC  COMPOUNDS. 
By  Prof.  Virgin  Coblentz. 
The  object  of  this  paper  is  to  present,  in  as  concise  a  manner  as  possible, 
the  outline  of  a  few  selected  topics  bearing  upon  this  subject.  At  a  future  date 
a  more  complete  presentation  of  this  subject  will  be  made.  Those  interested 
in  modern  synthetics  will  find  a  general  resume  of  the  subject  in  the  Journal  of 
the  Society  of  Chemical  Industry ,  Vol.  xvii,  No.  8. 
The  long  well-known  fact  that  certain  relations  existed  between 
physiological  action,  molecular  weight  and  isomorphous  inorganic 
bodies  led  to  a  similar  study  of  organics.  This  subject  received  its 
direct  stimulus  by  Fischer's  discovery  of  Kairine  in  1882,  followed 
by  the  accidental  discovery  of  the  antipyretic  properties  of  acetan- 
ilid  in  1887. 
A  proof  that  a  close  relationship  exists  between  chemical  consti- 
tution and  physiological  action  is  shown  by  the  fact  that  certain 
changes  in  chemical  structure  or  constitution  causes  like  changes  in 
the  physiological  action  of  similar  bodies;  further,  the  addition  of 
certain  groups  to  compounds  of  different  action  produces  bodies  of 
similar  physiological  action  or  are  alike  rendered  inactive. 
According  to  Crum  Brown  and  Fraser  the  methylating  of  differ- 
ent alkaloids  of  different  physiological  action  produces  compounds 
which  paralyze  all  the  motoric  nerve  terminals  like  curarin. 
The  introduction  of  the  carboxyl  (COOH)  or  the  sulphonic  acid 
(SO3H)  groups  into  bodies  of  well  denned  toxic  properties,  results 
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