Am.  Jour.  Pbarm.l 
Jan.,  1893.  / 
vS 'taming  Vegetable  Tissues. 
19 
100  cc.  of  70  per  cent,  alcohol  is  then  added,  and  the  solution 
filtered  if  necessary  before  use.  The  sections,  after  staining,  are 
transferred  to  alcohol  (70  per  cent.),  containing  half  to  one  per  cent, 
of  hydrochloric  acid  (sp.  gr.  ri6).  Plasmatic  stains  color  the  tissue 
uniformly  and  are  used  to  color  the  ground  for  the  sake  of  contrast, 
when  nuclear  and  specific  stains  have  been  previously  used.  Alcohol 
must  be  removed  from  the  sections  by  placing  them  for  a  minute 
in  distilled  water,  after  which  they  may  be  transferred  to  the 
plasmatic  stain.  To  follow  haematoxylin  this  may  be  water  soluble 
eosin  (1  grm.  in  40  cc.  of  s.v.r.,  and  160  cc.  aq.  dest.),  erythrosin 
(same  strength  as  eosin),  or  orange  (2  grm.  in  20  cc.  of  s.v.r.,  and 
80  cc.  aq.  dest.).  After  using  carmine,  picric  acid  (I  grm.  in  IOO 
cc.  of  70  per  cent,  alcohol)  affords  a  suitable  contrast.  In  each 
instance  afterwards  wash  with  90  per  cent,  alcohol.  Specific  stains, 
as  their  name  implies,  are  used  to  distinguish  certain  elements  only 
from  the  mass  of  tissue.  Carmine,  haematoxylin  and  most  of  the 
aniline  dyes  stain  unaltered  cellulose,  whilst  lignified  tissue  may  be 
permanently  stained  with  methyl  green  (0*25  grm.  in  20  cc.  of  s.v.r., 
and  80  cc.  aq.  dest.).  Squire's  process  for  double  staining  stem  and 
root  sections  containing  cellulose  and  lignified  tissue  is  to  first  rinse 
in  distilled  water,  then  place  in  methyl  green  solution  for  three  or 
four  minutes  ;  again  rinse  in  water,  wash  in  90  per  cent,  alcohol  for 
five  or  ten  minutes,  place  in  Grenadier's  alcoholic  borax  carmine 
for  fifteen  or  twenty  minutes,  rinse  quickly  in  water,  and  pass 
through  90  per  cent,  alcohol.  Chlorzinc  iodine1  colors  cellulose 
blue,  and  lignin  yellow  or  yellowish  brown,  the  latter  being  also 
colored  red  with  phoroglucin  (1  grm.  in  20  cc.  s.v.r.,  and  80  cc.  aq. 
dest.)  and  strong  hydrochloric  acid,  and  yellow  with  aniline  chloride 
(2  grm.  in  65  cc.  of  s.v.r.,  35  cc.  aq.  dest.,  and  2  cc.  strong  HC1). 
Hoffmann's  blue  or  eosin  are  specially  useful  for  distinguishing  sieve 
areas.  Particulars  of  other  specific  stains  and  their  uses  may  be 
found  in  Poulsen's  "  Botanical  Micro-Chemistry."  For  permanent 
preparations  of  fresh  vegetable  tissues  haematoxylin  will  be  found  the 
most  useful  single  stain,  since  by  controlling  its  action  it  is  quite 
possible  to  differentiate  all  the  constituents  with  it,  each  one 
displaying  a  distinct  shade  of  blue,  marking  it  off  clearly  from  the 
1  Schulze's  solution  :  prepared  by  evaporating  100  cc.  liq.  zinci  chlor.,  B.P. 
to  70  cc,  and  dissolving  in  it  10  grammes  potassium  iodide.  Add  0*2  gramme 
iodine,  and  shake  frequently  until  saturated.   {"  Methods  and  Formulae,"  p.  55.) 
