208 Gastric Glands of Dog after Gastroenterostomy 
a little fixing fluid applied to the muscularis mucose by a pipette. After 
two or three minutes the pins were removed and the strip dropped into 
a bottle of the fixative. This method prevents the curling of the strip 
due to the contraction of the muscularis mucosx, which otherwise disturbs 
the relations of the glands. 
Small pieces of mucous membrane were removed at the time of the 
operations and fixed in various fluids. ‘These served as controls with 
which glands modified as the result of the operations were compared 
later, and also as material in which the normal, healthy structure of the 
mucous membrane was studied. 
Experiments were made with very many fixing fluids and it was 
found that the one which gave the best all-around results was made of 
formalin, 3 per cent aqueous solution of potassium bichromate, saturated 
aqueous solution of mercuric chloride, and water, in equal parts. Strips 
of mucosa were left for two hours in this fluid, then washed and 
dehydrated. It is difficult to fix both the zymogen granules and the 
cytoplasm in the cells of a dog’s gastric glands. The zymogen granules 
are more difficult to fix than in cats or rabbits, and are not fixed at all 
in Zenker’s fluid, and very poorly in Bensley’s fluid or Bouin’s. Kopsch’s 
fluid fixes the granules well and the cytoplasm poorly. Bensley’s and 
Bouin’s fluids fix the cytoplasm well but the zymogen granules poorly. 
The above solution gave very good results for both. 
Paraffin sections three or four micra thick were cut, and fixed to the 
slide by the water method. The following stains were found most in- 
structive. Neutral gentian as used by Bensley, 00, gives a very definite 
blue stain of the zymogen granules. In material fixed in Bensley’s fiuid 
it does not stain the prozymogen, but in formalin fixations I have 
usually found it to stain the prozymogen purple. A mixture of equal 
parts of saturated aqueous solutions of acid fuchsin and orange G stains 
the granules of the parietal cells a definite pink in a minute or two, 
and if it be followed by a saturated aqueous solution of toluidine blue 
for one or two minutes, there is produced in addition a very pretty 
metachromatic pink tint in the surface mucus and in the thece of the 
cells of the surface and stomach pits, and also a deep blue color of the 
zymogen granules and the prozymogen. Mayer’s muchzematein and muci- 
carmine were also used to stain mucus. The former gave the more 
constant and the latter the more beautiful results. The modifications 
of its preparation suggested by Rawitz, 99, who evaporated the mixture 
of carmine, aluminum chloride and water to dryness at a low tempera- 
ture before dissolving in alcohol, and by Bensley, who used Mayer’s stock 
