The palpebral conjunctiva consists of a chorion, the free surface of which presents papillae, constituting what is called the papillary body, and the whole is covered by an epithelium.
The chorion of the palpebral conjunctiva is intimately incorporated with the tarsal fibro cartilages, so that the latter and their investing conjunctiva might be considered together as constituting a compound or fibro-mucous struc ture. Beyond the cartilages the chorion ap pears in its independent and separable form as a felt-work composed of an interlacement of filamentous cellular tissue, and is the nidus for the ramification of the vessels and nerves.
Papillary body.—If the upper eyelid be everted and examined, the moisture being first wiped off from its surface, under different direc tions of the light, an appearance is observed as of a shining surface beset with small brilliant grains, as if minutely shagreened. This ap pearance is more or less distinct in different individuals and most so after death.
The appearance described is produced by numerous papilla;, considered nervous by Ruysch,* and small glands by Miiller,t and, after him, by most other authors. Eble! objects to this view of the matter, and asserts that the pa iliac are quite distinct from mucous glands, and are the same as the papillae found on other mucous surfaces, and that they particularly resemble the papillm of the mucous membrane of the gums and inner surface of the aim nasi. Eble, however, adds that these papillae present themselves in all the mucous membranes in a manner quite analogous to glands, and he thinks that the mucus of mucous membranes is the product of the secretion of the papillary body. And this is equally applicable to the secretion of the palpebral conjunctiva, whence it would appear that Muller and Eble really do not differ in opinion, but only in the terms they employ to express it.
The part where the papillary body appears least distinctly is between the edge of the eyelid and the groove on the posterior surface above mentioned. The palpebral conjunctiva all beyond the groove presents the papillary body in a more decided form, and the development of it goes on increasing to some distance beyond the orbital margin of the tarsus. The con junctiva covering the lacrymal caruncle, as also the greatest part of the semilunar fold, present no papillary body. Towards the lacrymal
points there is found a great number of pretty apparent papil I w.
The papillary body is very vascular. It is the morbid development of it which constitutes the so-called granulations of the eyelids in the puro-mucous ophthalmia;; of which indeed the papillary body appears to be the peculiar seat. An inflammation suddenly affecting a healthy conjunctiva from atmospherical causes is what is conventionally called a catarrhal ophthabnia. If this be allowed to fall into a chronic state, or if the conjunctiva has been affected by a less marked inflammatory action for a time, the papillary body becomes hypertrophied. In this state it forms as it were a new organ ready to be affected by a form of disease which a healthy conjunctiva is not all at once so prone to as sume. Mere congestion caused by over exertion of the eyes, or by heavy caps and high tight collars, as Dr. Vleminckx thinks, together with fatigue, exposure, want of cleanliness, abuse of stimulating liquors, &c., may give rise to this unnatural development of the papil lary body of the conjunctiva, and so predispose in a particular manner, on the occurrence of any atmospherical influence, to an attack of con junctivitis, and that rather of the form of the Egyptian ophthalmia than of a simple ca tarrhal.
Epithelium of the palpebral conjunctiva. " It is extremely difficult," says Eble,* " to distinguish this on so fine a membrane. Al though I have succeeded, by maceration in boiling water, in detaching it in part from the eyelids of an ox, I have not again been able to convince myself of the exactness of the obser vation as I could have wished." J. F. Meckcl doubted the existence of an epithelium. Eble says again that he would, however, admit its presence on the conjunctiva rather from analogy than from observation. Here is a good example of the assistance derivable from the microscope, two such observers as Meckel and Eble unable with the naked eye to determine the existence of a structure which later observers with the microscope have fully established. We shall return to the subject in speaking of the epithe lium of the conjunctiva bulbi.