Am.  .lour.  Pharin.  > 
November,  IPOS,  i 
Alkalinity  of  the  Blood. 
507 
tubing  is  fitted  over  the  sharpened  end  of  the  blood  pipette;  by 
compressing  the  rubber  bulb  the  acid  solution  is  forced  through  the 
pipette  into  the  test  tube,  the  aperture  in  the  glass  bulb  being  closed 
before  the  pressure  is  relaxed  to  prevent  the  mixture  of  the  acid 
solution  and  the  blood.  Having  done  this,  the  test  tube  is  inverted 
several  times  while  still  being  attached  to  the  reagent  pipette,  care 
being  exercised  to  keep  the  reagent  pipette  in  a  vertical  position,  to 
avoid  a  gravitation  of  the  acid  solution  into  the  rubber  bulb  of  the 
reagent  pipette,  thus  preventing  a  chemical  action  upon  the  rubber 
nipple  with  the  formation  of  a  flocculent  precipitate.  The  interval 
{Fig.  1,  A)  between  the  closed  end  of  the  tube  and  the  first  marking, 
o,  should  be  placed  in  the  cleft  of  the  spectroscope  (Fig.  1,  D)  and 
observations  be  taken  as  to  the  existence  of  bands  of  oxyhemo- 
globin. Should  these  bands  be  present  the  careful  addition  of  acid 
solution  is  necessary.  As  the  bands  become  fainter  and  fainter  we 
know  that  we  are  approaching  the  point  of  neutralization,  and  it 
becomes  necessary  to  add  the  acid,  one  drop  at  a  time ;  then  invert 
the  test  tube  and  examine  with  the  spectroscope  as  before.  After 
performing  several  tests  with  this  instrument  it  will  not  be  necessary 
to  apply  the  spectroscope  so  frequently  to  determine  the  point  of 
neutralization,  as  the  eye  quickly  learns  to  detect  this  characteristic 
change  by  the  color  of  the  blood  mixture.  When  the  bands  of 
oxyhemoglobin  suddenly  disappear  the  observation  is  at  an  end* 
It  is  then  only  necessary  to  read  the  result  from  the  scale  on  the 
test  tube,  which  is  graduated  in  cubic  centimeters  and  the  equiva- 
lents expressed  in  milligrams  of  sodium  hydrate  to  100  c.c.  of  blood. 
As  a  uniform  light  is  necessary  for  physiological  experiments, 
artificial  illumination  should  be  selected  as  being  always  available. 
An  open  gas-light  was  employed  in  our  experiments  entirely,  and 
the  relation  of  the  spectroscope  to  the  source  of  illumination  kept 
always  constant. 
The  scale  of  equivalents  computed  from  a  basis  of  15  mgs.  of 
blood  to  2  c.c.  of  acid  solution,        of  the  normal,  is  as  follows  : 
Mgs.  of  NaOH  to 
c.c.  of  reagent  I00  c.c.  of  blood. 
26  345 
