MOLECULAR  DISSYMMETRY  OF  ORGANIC  PRODUCTS.  105 
it.  Excepting  the  hemihedric  faces,  there  is  a  perfect  resem- 
blance between  the  two  forms. 
Who  could  doubt  after  that,  the  relations  of  molecular  arrange- 
ments of  these  two  salts  ?  Is  it  not  evident  that  we  have  here 
to  deal  with  a  malic  acid  identical  to  the  natural,  except  the 
simple  suppression  of  its  molecular  dissymmetry  ? 
This  is  the  natural  malic  acid  untwisted,  if  I  may  so  express 
it.  The  natural  acid,  in  the  arrangement  of  its  atoms,  is  a  wind- 
ing stair;  this  one  is  the  same  stair,  formed  of  the  same  steps, 
but  straight,  instead  of  being  spiral. 
It  might  now  be  asked  if  the  new  malic  acid  is  not  the  para- 
tartaric  of  the  series,  that  is,  the  combination  of  the  right  malic 
acid  with  the  left  malic  acid.  That  is  scarcely  probable ;  for 
then  not  only  with  an  inactive  body  we  would  have  made  an 
active  body,  but  would  have  made  two,  one  right  and  one  left. 
Besides,  I  have  ascertained  that  just  as  there  exists  a  non- 
dissymmetric  inactive  malic  acid,  so  there  is  also  a  non-dissym- 
metric inactive  tartaric  acid,  very  different  from  paratartaric 
acid,  and  which  cannot  be  resolved  into  right  tartaric  and  into 
left  tartaric  acids.  Here  it  cannot  be  doubted  that  we  have  to 
deal  with  right  or  left  tartaric  acid  rendered  non-dissymmetric. 
I  have  also  discovered  inactive  amylic  alcohol,  which  yields  a 
whole  series  of  inactive  products  corresponding  to  the  series  of 
active  amylic  alcohol. 
Thanks  to  the  discovery  of  inactive  bodies,  we  are  in  posses- 
sion of  a  fruitful  idea :  a  substance  is  dissymmetric,  right  or 
left,  by  certain  modes  of  isomeric  transformations,  which  must 
be  sought  and  discovered  in  each  particular  case;  it  may  lose 
its  molecular  dissymmetry,  untwist  itself,  to  use  a  coarse  illus- 
tration, and  effect  in  the  arrangement  of  its  atoms  a  disposition 
with  a  superposable  image.  So  that  every  dissymmetric  sub- 
stance offers  four  varieties,  or  rather  four  distinct  subspecies : 
the  right  body,  the  left  body,  the  combination  of  the  right  and 
the  left,  and  the  body  which  is  neither  right  nor  left,  nor  formed 
by  the  combination  of  the  right  and  left. 
VII. 
This  general  conclusion  from  the  preceding  studies,  throws 
new  light  upon  our  ideas  of  molecular  mechanism.    We  see  that 
