118 The Cardiac Glands of Mammals 
97, and Edelmann, 89, agree that the contents of the cells do not stain 
with mucin stains. In view of the fact that Schaffer used for this pur- 
pose mucicarmine and muchematein as recommended by P. Mayer, and 
that my results with similar solutions are directly opposed to his, inas- 
much as I succeeded in staining the secretion in the cells of the cardiac 
glands as well as those of the surface epithelium, it may be of interest 
to discuss briefly the reasons of the discrepancies in our results. Some 
reference has already been made to the probably great chemical diver- 
sity of the mucins and to the work of Mayer on their staining proper- 
ties. In the course of this paper he says: 
“Ich selber habe bisher das Wort Mucin geflissentlich vermeiden und 
dafiir stets von Firbung des Schleimes gesprochen. In der That wissen 
wir vom Schleime der hoheren Thiere chemisch noch recht wenig und von 
dem der allermeisten Wirbellosen so gut wie gar nichts. Oben habe ich 
bereits angedeutet dass die Schleime sich gegen einen und denselben 
Farbstoff sehr verschieden verhalten, indem ich bei Besprechung der Los- 
ungen von Hamatoxylin oder Hamatein sagte: In der Regel farbt sich 
der Schleim, oder: in der Regel fiirbt er sich nicht. Das sollte heissen: 
die von mir geprtiften Arten Schleim sind je nach ihrer Provenienz ver- 
schieden. Man konnte da eine formliche Reihe aufstellen, die mit solehem 
Schleime zu beginnen hitte, dessen Fairbung kaum zu verhindern ist, und 
mit solehem enden witirde, der sich kaum noch firben lasst. Jener ist z. 
B. bei Muscheln vertreten dieser findet sich im Darm von Homo.” 
I have found that not only do different mucins stain with different 
degrees of readiness in Mayer’s solutions, but that by modifying the 
composition of the solution or the mode of applying it, many mucins 
which stain with difficulty in the ordinary method may be made to take 
the color readily. For example, if a longitudinal section in celloidin 
of the pylorus of man be placed in Mayer’s muchematein (Hematein 
.2 grammes, aluminium chloride, .1 gramme, 70% alcohol, 100 cc.), only 
the goblet cells of the surface epithelium and of the glandule intesti- 
nales stain. If the strength of the solution in hematein and aluminium 
chloride is doubled, then the goblet cells stain strongly and a faint 
reaction is obtained in the epithelial cells of the stomach and of the 
pyloric foveole. If the strength of the solution is increased fivefold, so 
that it contains one per cent of hamatein and one-half per cent of 
aluminium chloride, both the secretion of the goblet cells in the intes- 
tine, and of the epithelium in the stomach, stains intensely and an 
equally vigorous stain is obtained in the cells of the duodenal glands 
(glands of Brunner) and in the cells of the pyloric glands. Practically 
the same result was obtained with mucicarmine. With the diluted 
solution recommended by Mayer, only goblet cells were stained, but if 
