208 
DEPARTMENT OF SURGERY. 
are partial when they involve only part of the cornea (Fig. 
47-B) ; complete , when the entire cornea is bulged out anteri¬ 
orly (Fig. 47-A) ; and racemose, when the cornea presents a 
number of protrusions that are sometimes linked together. 
Most all staphylomata are caused by increased intraocular 
pressure ; and this pressure produces some pathological lesion 
in the structures of the cornea which allows it to become dis¬ 
tended. 
In a vertical section of the cornea five well developed layers 
are recognized, which we will name trom without in : 
1. Anterior epithelial layer. 
2. Anterior limiting membrane. 
3. Substantia propria ( proper substance ). 
4. Posterior limiting membrane (DescemePs). 
5. Endothelial layer. 
1. The anterior epithelial layer is a continuation of the 
ectodermic portion of the conjunctiva, and consists of from six 
to eight layers of squamous cells ; the deep layer of cell, how¬ 
ever, may be considered low columnar, and rest upon the an¬ 
terior limiting membrane which is the matrix of the epithelial 
layer ( basement membrane). The epithelium is thickest near 
the periphery and thinnest at the centre. 
2. The anterior limiting membrane, or Bowman’s mem¬ 
brane, belongs neither to the elastic nor white fibrous connect¬ 
ive tissue. It is well supplied with nerve fibres which enter 
the epithelium, which covers it; it is a highly developed base¬ 
ment membrane, which is thickest at the centre of the cornea, 
and is frequently invaded by superficial ulcers of the cornea. 
3. The substantia propria , or proper substance , constitutes 
the bulk of the cornea and is composed of bundles of connective 
tissue fibrils held together by interfibrillar cement, and arranged 
into lamellae. The connective tissue cells are located between 
the lamellae in the corneal spaces. These corneal spaces are 
larger than the connective cells which affords a passage for the 
nutrient juices that supply the non-vascular cornea with, nutri¬ 
tion. Between these spaces are communications (<canaliculi ), and 
between the fibrillae, in the interfibrillar cement, is the location 
of the lymph spaces. When normal this layer is always trans¬ 
parent and any cloudiness or haziness of the cornea is generally 
due to some pathological lesion of this substance. 
4. The posterior limiting membrane , or membrane of Des- 
cemet , is a well defined membrane, thickest at the periphery, 
and composed of very elastic tissue. It can be separated from the 
