2 
CYSTIC TUMOUR IN LUMBAR REGION OF A DOG. 
equal size, which contained about four ounces of fluid, having 
the appearance of pus slightly tinged with blood. This fluid 
under the microscope was found to contain a large quantity 
of cholesterine, with exudation-corpuscles and blood-discs. 
In the interior of the cyst which was last opened there was 
a small detached tumour of the size of a chestnut, smooth 
on the surface, and quite firm in texture. To the interior of 
the walls of the two cysts were attached small tumours, 
varying in size from a pea to a hazel-nut, and on the surface 
of the lining of the cysts a quantity of flocculent white matter 
was deposited. 
The accompanying illustration will convey an idea of the 
structure of the morbid growths, which were all composed of 
the same elements. At the part marked a, the appearance of a 
section of the tumour under the inch-objective is depicted ; the 
dark centres are the openings apparently of sebaceous follicles, 
and the concentric lines represent layers of epithelium lining 
the follicles, and also layers of white fibrous tissue imme- 
diately extern to them. All these elements are more per- 
fectly shown at b, which represents a single section of one 
of the follicles magnified 600 diameters. 
