538 A. B. DAWSON 
distinguished in many cases, but in preparations stained only 
with a plasma stain a small quantity can often be distinguished 
in the immediate vicinity of the nuclei. The nuclei are smaller 
than those of the granular glands and are usually flattened against 
the gland wall, appearing angular in radial sections and round 
or oval in tangential sections of the gland. They invariably 
stain deeply in haematoxylin and retain their color even after 
the nuclei of the surrounding tissue have been almost completely 
decolorized. They show very little chromatin structure, but 
appear as homogeneous masses. 
The fresh secretion is clear and slimy. In sections of fixed 
material it usually appears fibrous or vesicular. The fibers, 
when present, always lead toward the duct, giving one the 
impression of a viscid substance in motion (fig. 12). Besides 
differing so greatly from the granular secretion in general appear- 
ance, the clear secretion also reacts very differently to stains. 
The contents of the glands are stained blue by Mallory’s connec- 
tive-tissue method, and with van Gieson’s method the secretion 
takes on a clear red or pink without a trace of the yellow 
invariably found in the granular glands. In iron haematoxylin 
the secretion is left practically unstained, but in either Dela- 
field’s or Ehrlich’s haematoxylin it takes a decided blue color, 
especially if the stain is a little heavy and the sections are ‘blued’ 
in an ammoniacal solution. Hoyer (’90) and Nicoglu (’93) have 
used thionin as a specific stain for mucus and found that the 
glands were stained a red-violet. I have used thionin success- 
fully in staining these glands, but was not able to retain the red- 
violet color when the sections were passed up through the alcohols 
and cleared preparatory to mounting in balsam. Preparations 
stained and examined in water, however, gave the typical color 
reaction, but when they were dehydrated and cleared, the red 
was entirely gone and the secretion was left a deep blue. ‘Thionin 
has absolutely no effect on the granular secretion. Hubbard 
(03) and Esterly (04) were unable to obtain any color reaction 
in the mucous glands with thionin. Weigert’s resorcin-fuchsin, 
a selective stain for elastic tissue, while it has no effect on the 
granular glands, always colors the mucous glands a deep purple 
