Am.  Jour.  Pharm. 
May,  1915. 
Book  Reviezvs. 
223 
grammes  of  sodium  chloride.  Such  a  draft  upon  the  tissues  could 
not  be  continued  indefinitely  unless  salt  were  supplied  in  correspond- 
ing amount.  Bunge's  personal  experiment  was  not  an  unreasonable 
one,  for  it  is  calculated  that  when  potatoes  form  the  bulk  of  a  man's 
ration  twice  as  much  potassium  may  be  ingested  as  in  this  trial. 
There  is,  therefore,  no  doubt  that  salt  is  a  necessary  addition  to 
diets  in  which  the  ratio  of  potassium  to  sodium  is  unusually  high. 
The  instinctive  craving  for  it  is  a  marvellous  instance  of  the  almost 
infallible  correctness  of  such  impulses.  Bunge  has  recorded  the 
use  by  an  African  tribe  of  the  ash  of  a  certain  tree  as  a  seasoning 
for  their  food.  Most  kinds  of  wood  reduced  to  ashes  would  yield  a 
mixture  over-rich  in  potassium,  which  would  be  a  most  undesirable 
adjunct  to  other  articles  of  vegetable  origin.  But  the  tree  in  favor 
with  these  people  was  the  rare  exception;  its  ash  contained  a  most 
unusual  proportion  of  sodium  compounds.  It  is  rather  painful  to 
fancy  the  tedious  succession  of  experiments  by  which  the  ancestors 
of  this  tribe  eliminated  various  kinds  of  wood,  and  pleasant  to 
imagine  the  satisfaction  realized  when  the  fortunate  choice  was 
finally  made. 
BOOK  REVIEWS. 
Chemistry  of  Familiar  Things.  By  Samuel  Schmucker 
Sadtler,  S.B.  Philadelphia  and  London:  J.  B.  Lippincott  Company. 
There  are  a  great  many  persons  who  have  not  received  any  special 
training  in  the  sciences  but  who  are  nevertheless  interested  in  the 
results  of  scientific  research,  and  for  them  a  book  which  is  readable 
and  accurate  is  very  welcome.  There  has  always  been  a  demand  for 
popular  books  treating  of  chemistry,  botany,  biology,  astronomy,  etc. 
In  view  of  the  application  of  the  studies  of  chemistry  not  only  to  the 
development  of  industrial  processes  but  their  importance  to  the  life 
of  mankind  a  book  like  the  present  one  by  Mr.  Sadtler  will  be  much 
appreciated. 
In  the  first  chapter  we  find  enough  elementary  chemistry  to 
enable  the  reader  to  understand  and  appreciate  much  of  the  informa- 
tion which  follows  in  the  subsequent  chapters.  Among  the  subjects 
discussed  may  be  mentioned :  Historical  Development  of  Chemistry; 
The  Periodic  System  of  Elements ;  The  Chemistry  and  Production  of 
Light ;  Heat,  Combustion  and  Insulation ;  Air,  Oxidation  and  Venti- 
lation ;  Water ;  Alkalies  and  Salts ;  Metals ;  Gold  and  Silver ;  Chem- 
