684 
Smell-Shock 
(  Am.  Jour,  Pharm. 
(       Oct.,  1921. 
knew  the  geology  of  the  land  and  the  smell  of  the  soil.  Generally 
speaking,  however,  the  average  man  has  limited  olfactory  power, 
unless  he  has  improved  the  sense  by  exercising  it. 
In  endeavoring  to  connect  the  sense  of  smell  with  the  chemical 
constitution  of  the  substance,  Sir  William  Ramsay  has  pointed  out 
that,  as  a  general  rule,  substances  having  a  low  molecular  weight 
have  either  no  smell  or  simply  cause  irritation  of  the  nostrils.  He 
also  shows  that  in  the  carbon  compounds  increase  of  specific  gravity 
as  a  gas  is  associated  to  a  certain  point  with  a  sensation  of  smell. 
It  has  also  been  pointed  out  that  compounds  of  elements  belonging 
to  the  same  group,  according  to  the  periodic  law,  have  sometimes 
odors  of  a  similar  character.  But  beyond  this,  there  is  no  classifica- 
tion of  odors.  We  must  be  content  to  describe  an  odor  as  pleas- 
ant, disagreeable,  aromatic  or  characteristic  and  so  on.  This  sort 
of  description  may  mean  anything  or  nothing,  when  it  is  considered 
that  an  odor  may  appeal  to  one  person  as  being  pleasant  and  to 
another  as  being  obnoxious. 
'As  to  the  intensity  of  odors,  it  is  said  that  musk  to  the  extent 
of  only  four  one-hundredths  of  a  milligram  per  liter  of  air  is  detect- 
able and  thus  it  is  that  a  grain  or  two  of  musk  will  scent  a  room 
for  years  and  at  the  end  of  the  time  no  appreciable  loss  of  weight 
can  be  detected. 
As  to  the  susceptibility  of  humans  to  odors,  some  persons  may  be 
sensitive  to  some  odors  while  they  do  not  recognize  others.  It  is 
not  uncommon  for  students  to  fail  to  recognize  hydrocyanic  acid  in 
a  solution  given  them  for  analysis. 
The  detection  and  identification  of  odors  is  of  much  importance 
to  pharmacists  and  it  was  with  the  thought  of  determining  their 
responsiveness  that  the  following  experiment  was  carried  out.  A 
series  of  fifteen  liquid  odorous  substances  was  submitted  to  twenty 
men  selected  at  random.  Six  of  these  men  were  members  of  the  • 
faculty  of  the  Philadelphia  College  of  Pharmacy,  all  of  whom  had 
had  pharmaceutical  training.  Six  were  students  with  varying  drug 
store  experience  and  the  remaining  eight  were  graduate  and  prac- 
ticing pharmacists.  The  purpose  of  the  test  was  to  identify  specific 
odors  and  consequently  color,  taste  and  mobility  were  not  to  be 
taken  into  account.  The  substances  submitted  were  as  follows :  Oil 
of  turpentine,  ethyl  alcohol,  oil  of  cinnamon,  vinegar,  oil  of  orange, 
kerosene,  creosote,  oil  of  sassafras,  methyl  salicylate,  benzaldehyde, 
gasoline,  ether,  oil  of  anise,  linseed  oil  and  oil  of  nutmeg.    The  re- 
