222  Salt  and  its  Relation  to  Nutrition,    /Am.  Jour  Pharm. 
I       May,  191o. 
marked  contrast  to  many  of  the  herbivora,  like  cattle,  sheep,  and 
deer,  which  are  very  fond  of  salt. 
The  Arctic  explorer  Stefanson  has  recently  reported  a  striking 
instance  of  the  objection  to  salt  which  accompanies  the  use  of  a  flesh 
diet.  The  Esquimaux,  whom  he  knows  so  well,  have  little  vegetable 
food.  When  he  settled  among  them  he  was  embarrassed  by  their 
demands  upon  his  hospitality.  Policy  dictated  that  he  offer  them 
food  on  all  occasions,  but  there  was  every  prospect  that  his  stores 
would  be  rapidly  depleted.  The  situation  was  relieved  by  a  simple 
device.  It  was  only  necessary  to  salt  the  food  moderately — merely 
to  his  own  liking — to  deter  his  visitors  from  making  inroads  upon  it. 
The  requirements  of  courtesy  were  satisfied  and  the  provisions  were 
conserved. 
When  a  sample  of  food  is  burned  as  completely  as  possible  the 
mineral  constituents  remain  as  ash.  Chemical  analysis  of  this  ash 
leads  to  very  different  findings  in  the  case  of  different  foods.  Several 
acids  and  bases  will  always  be  found.  We  will  consider  only  the 
occurrence  of  sodium  and  potassium.  The  ratio  between  the  quan- 
tities of  these  two  bases  is  widely  varied,  though  in  the  great  ma- 
jority of  instances  potassium  is  the  more  abundant.  In  animal  foods 
the  disparity  is  not  marked,  but  in  most  vegetable  substances  it  is 
striking.  For  example,  the  proportion  of  potassium  to  sodium  in 
meat  (veal)  is  4  to  1,  while  in  potato  it  is  more  than  3  to  1. 
Can  we  recognize  a  causal  connection  between  the  excess  of 
potassium  in  a  vegetable  diet  and  the  craving  for  sodium  chloride 
which  is  attendant  on  the  use  of  such  a  diet  ?  Bunge  maintains  that 
we  can.  His  explanation  has  been  criticised  in  detail,  but  is  probably 
valid  in  its  main  thesis.  The  absorption  into  the  blood  of  a  quantity 
of  salts,  unlike  those  normally  present  there,  imposes  upon  the  kid- 
neys the  duty  of  restoring  standard  conditions.  If  the  chief  demand 
is  for  the  removal  of  potassium  compounds  the  task  will  soon  be  ac- 
complished. But  this  will  not  be  done  without  a  considerable  loss 
of  sodium  chloride.  It  would  be  remarkable  indeed  if  the  kidney 
cells  could  select  all  the  foreign  ions  and  not  occasionally  let  slip  some 
of  the  much  more  numerous  native  ones. 
Bunge  was  able  to  demonstrate  upon  himself  the  fact  that  an  ex- 
cessive intake  of  potassium  salts  does  lead  to  a  loss  of  sodium 
chloride.  He  swallowed  as  much  potassium  phosphate  and  citrate  as 
he  could  tolerate  and  subsequently  excreted  all  the  potassium — 
equivalent  to  18  grammes  K20 — but  simultaneously  eliminated  6 
