Am.  Jour.  Pharm. 
Nov.,  1889. 
Chemistry  of  Saliva. 
569 
which  is  readily  filtered,  deposits  no  precipitate  even  after  several 
hours,  and  is  not  affected  by  boiling.  It  has  an  orange-yellow  color, 
and  is  slightly  dextrogyrate.  Like  all  colloids  it  is  precipitated  from 
solution  by  very  small  quantities  of  sulphuric  or  nitric  acid,  sodium 
chloride  or  sulphate,  lead  acetate,  etc.  Alcohol  in  sufficient  quantity 
produces  the  same  result.  Colloidal  cellulose  does  not  reduce  Feh- 
ling's  solution,  gives  no  coloration  with  iodine,  and  differs  from  the 
achrodextrins  in  being  precipitated  by  small  quantities  of  salts.  If  a 
solution  is  dried  on  marble  which  has  been  rubbed  with  vaseline  and 
well  polished,  it  forms  brilliant,  semi-transparent  pellicules,  which 
swell  up  slightly  in  water  and  then  dissolve.  If  immersed  in  sul- 
phuric acid  of  60°  for  a  short  time,  or  in  acid  of  55°  for  a  longer 
time,  it  becomes  insoluble  in  water,  and  at  the  same  time  a  small 
quantity  of  dextrin  is  formed.  When  treated  with  nitric  acid  it  forms 
nitrocellulose  in  the  same  way  as  ordinary  cellulose,  and  becomes 
slightly  less  transparent. 
Thin  parchment-paper,  which  has  probably  been  prepared  with  a 
somewhat  weak  acid,  yields  colloidal  cellulose  to  boiling  water,  but 
thicker  paper,  which  has  been  treated  with  stronger  acid,  is  insoluble. 
Parchment-paper  may,  in  fact,  be  regarded  as  a  cellu]ar  tissue,  the 
pores  of  which  have  been  filled  up  with  colloidal  cellulose. 
THE  CHEMISTRY  OF  SALIVA.1 
By  De.  G.  Sticker. 
The  author  has  published  in  the  Deutschen  Medizinal-Zeitung  a 
long  and  highly  interesting  communication  upon  saliva,  and  the  por- 
tions more  important  to  pharmacy  are  here  reproduced  in  a  condensed 
form. 
Human  saliva  is  colorless  or  presents  a  somewhat  bluish  tinge  and 
has  a  sweetish  or  saline  taste.  The  specific  gravity  varies  between 
1*002  and  1*008,  but  under  a  purely  vegetable  diet  this  is  lowered. 
In  the  evening  and  after  the  different  meals  the  saliva  is  heavier  than 
in  the  morning  or  when  fasting ;  in  the  former  case  too  it  presents  an 
alkaline  reaction,  but  in  the  latter  it  reacts  faintly  acid.  With  an 
increased  consumption  of  amylaceous  food  the  alkali  in  the  saliva 
increases,  but  with  a  pure  flesh  diet  it  decreases.    Whilst  in  the  horse 
^rom  the  Apotheker-Zeitung,  reprinted  from  Phar.  Jour,  and  Trans.,  Aug.  3, 
1889,  p.  88. 
