346 
Book  Reviews. 
(Am.  Jour.  Pharm. 
X       July,  1910. 
routine  manufacture  of  essential  oils  on  a  large  scale  as  well  as  for 
their  special  scientific  investigations  on  new  essential  oils.  The 
example  thus  furnished  is  one  that  may  well  be  emulated,  as  already 
stated  in  a  previous  reference  to  the  publications  of  this  firm 
(Journal,  vol.  76,  1904,  p.  214),  for  after  all  the  manufacturer 
of  medicines  and  like  products  must  be  guided  by  the  same  ideals 
as  to  the  purity  and  efficiency  of  his  products  and  in  the  discovery 
of  new  and  valuable  substances,  as  the  practioners  of  medicine  and 
the  teachers  in  medicine  and  pharmacy,  if  the  practice  and  the  theory 
are  to  go  hand  in  hand.  In  other  words,  the  manufacturer  of 
medicines  and  pharmaceutical  products  can  no  longer  afford  to  think 
alone  of  the  commercial  gains  on  his  products,  but  must  at  the  same 
time  be  imbued  with  a  motive  similar  to  that  which  impels  the  teach- 
ers and  practitioners  in  the  professions  named  to  devote  their  lives 
to  their  chosen  work  with  but  secondary  concern  as  to  the  pecuniary 
rewards. 
The  present  volume,  which  is  by  von  Rechenberg,  might  well  be 
employed  as  a  text-book  by  organic  chemists,  as  it  treats  of  the 
scientific  principles  involved  in  distillation  processes  in  a  manner 
which  is  illuminating  and  indeed  inspiring.  That  this  is  not  over- 
stated is  seen  in  the  mere  mention  of  the  contents  of  the  fourteen 
chapters  of  which  the  book  is  comprised:  (1)  Practice  of  distillation, 
involving  a  study  of  the  action  of  steam  in  plant  and  oil  distilla- 
tion; (2)  Dalton's  law  of  diffusion;  (3)  distillation  of  mixtures  of 
insoluble  fluids ;  (4)  distillation  under  reduced  or  increased  pres- 
sure; (5)  distillation  at  high  temperatures;  (6)  the  chemical-physi- 
cal changes  preceding  and  incident  to  plant-distillation;  (7)  special 
examples  of  distillation,  as  of  lavendar  flowers  in  Southern  France, 
the  distillation  of  herbs  in  Spain,  cajuput  distillation  in  Ceram,  cassia 
leaves  in  Southern  China,  the  distillation  of  coniferous  plants  in 
Switzerland,  the  distillation  of  cananga  flowers  in  Java,  of  rose  petals 
in  Bulgaria  and  linaloe  wood  in  Mexico;  (8)  the  influence  of 
molecular  association  and  dissociation  in  the  process  of  distillation  ; 
(9)  the  influence  of  higher  temperatures  with  and  without  pressure 
upon  individual  substances;  (10)  a  chapter  in  general  upon  solu- 
tions; (11)  the  distillation  of  mixtures  bordering  on  more  or  less 
soluble  constituents;  (12)  the  distillation  of  homogeneous  mixtures 
at  temperatures  less  than  the  boiling  point;  (13)  the  distillation  of 
homogeneous  mixtures  not  having  a  constant  boiling  point;  (14) 
the  distillation  of  labile  addition  compounds,  and  the  distillation  of 
homogeneous  mixtures  with  maximum  boiling  points.  H.  K. 
