570 
Chemistry  of  Saliva. 
Am.  Jour.  Pharm. 
Nov.,  1889. 
the  quantity  of  saliva  secreted  in  twenty-four  hours  will  amount  to 
four  to  six  kilograms,  it  amounts  in  grown  men.  to  from  500  to  1,500 
grams.  In  the  flesh-eating  dog  the  quantity  is  still  much  smaller, 
since  flesh-eaters  require  less  saliva  for  their  food,  which  is  rich  in 
water;  the  most  being  required  by  granivorous  animals  for  their 
relatively  dry  food. 
In  respect  to  diastatic  power  the  saliva  of  omnivorous  man  exceeds 
that  of  any  other  creature.  In  the  first  two  months  of  an  infant's  life 
the  diastatic  power  of  the  saliva  is  almost  without  exception  wanting. 
Occasionally  it  is  present  in  the  saliva  of  the  three  months'  child,  but 
the  more  intense  action  does  not  become  manifest  until  towards  the 
end  of  the  first  year.  The  toothless  child  should  therefore  obtain  only 
liquid  nourishment  and  have  flesh  given  to  it  only  after  the  appear- 
ance of  the  incisors  and  canine  teeth.  The  body  temperature  of  38° 
to  39°  C.  is  the  most  favorable  for  the  saccharifying  action  of  human 
saliva. 
Ptyalin  is  paralyzed  by  alcohol  and  the  diastatic  action  of  the  saliva 
is  also  stopped  by  large  quantities  of  alkalies  or  acids.  One  per  cent, 
solution  of  carbolic  acid  in  contact  with  saliva  deprives  it  after  a  time 
of  the  power  to  decompose  starch.  A  0*2  per  cent,  solution  of  sali- 
cylic acid  diminishes  the  salivary  fermentation,  and  a  1  per  cent- 
solution  stops  it  entirely.  But  it  is  remarkable  that  this  action  is  not 
exercised  by  the  sodium  salt  of  salicylic  acid,  notwithstanding  that  it 
possesses  antizymotic  properties.  A  similar  action,  but  to  a  greater 
extent,  is  however  shown  by  salicylic  acid  upon  emulsin,  myrosin,  and 
synaptase,  whilst  pepsin  and  trypsin  can  be  protected  from  putrefaction 
by  the  addition  of  salicylic  acid  without  their  specific  action  being 
injured  in  the  least.  Borax  does  not  kill  diastase,  whilst  quinine  and 
arsenious  acid  paralyze  the  ferment  only  in  very  large  doses.  Quinine, 
strychnine,  morphine  and  curare  in  small  quantities  promote  the  fer- 
mentative action  of  the  salivary  liquid,  in  accordance  with  the  known 
pharmacological  axiom  that  small  doses  frequently  excite  while  large 
doses  paralyze.  A  similar  behavior  is  shown  by  the  pancreas-ptyalin. 
Sodium  chloride  solution  up  to  a  strength  of  3*85  per  cent,  promotes 
the  fermentative  action  of  saliva,  a  higher  percentage  diminishes  it. 
The  same  action  is  shown  by  sodium  sulphate  and  ammonium  chloride, 
whilst  the  fermentative  action  is  depressed  by  ammonium  nitrate  and 
potassium  chloride.  At  a  temperature  of  38°  to  40°  C.  salicin  is  con- 
verted by  the  salivary  ferment  into  sugar  and  saligenin,  but  it  is  not 
