150 Tue Microscope. 
STUDIES IN HISTOLOGY. 
Cc. H. STOW ELL. 
METHODS OF EXAMINING. 
MUCOUS TISSUE. 
MALL pieces of the umbilical cord of any mammalian 
foetus are placed in Miiller’s fluid and afterwards in alcohol 
to complete the hardening. Very thin transverse sections are 
made, carefully stained, and examined in glycerine, or cleared 
and mounted in balsam. Thin sections may be studied to ad- 
vantage by pencilling after staining, although better success 
will follow this method if only the fresh specimens be used, 
the thin sections having been made by aid of the freezing 
microtome. 
Subcutaneous tissue may be removed from any young em- 
bryo, teased, stained and mounted in glycerine. 
WHITE FIBROUS TISSUE. 
A small piece of subcutaneous tissue is placed on a slide 
and moistened with the salt solution. Bundles of the fibrils 
are seen with their wavy appearance. A few elastic fibres may 
be seen here and there in the field. Acetic acid will cause 
this fibrous appearance to disappear and the tissue to look 
like a mass of jelly. The cells are seen without much diffi- 
culty in a specimen or intermuscular fascia. A small portion 
of this is excised with the scissors and by the aid of needles 
carefully spread out on a dry slide; the specimen is kept moist 
by occasionally breathing upon it. A drop of hematoxylin is’ 
now placed on a cover-glass which is inverted upon the speci- 
men. A drop of acetic acid is placed at the edge of the cover 
and the cells now show to good advantage. Specimens of this 
tissue may be teased from a tendon while fresh or the tendon 
may be hardened in chromic acid and longitudinal and trans- 
verse sections examined. 
For a permanent preparation, Cole recommends injecting 
the axilla of a recently killed kitten or young rat with a 1 per 
cent. solution of osmic acid. When the tissue has swollen, cut 
out the areolar tissue, place it on a slide, spread it out with 
needles and put on a drop of picrocarmine frequently renewed 
through 24 hours. Replace the staining with glycerine jelly 
and cover. Hematoxylin may take the place of the picrocar- 
