INFLAMMATIOy OF THE CONJUNCTIVA 403 



diicing consideral)le increase of the irritation already present. When 

 the atiection extends to the cornea, it may become opaque, and in more 

 severe cases cause uh-eration of the cornea (see Keratitis). 



Conjunctivitis follicularis of the membrana nictitans is a variety of 

 this disease (catarrhal conjunctivitis) that is generally chronic. This 

 is indicated by the appearance of large numbers of lymphatic follicles 

 upon the internal surface of the membrana mictitans. These follicles 

 stand out distinctly in the form of millet-seed bodies upon the surface 

 of the meml^rane. They are dark red and transparent, consisting of 

 ball-shaped accumulations of lymphoid cells. Soon they appear in 

 numerous masses, giving the membrane the appearance of a granulating 

 M-ound surface, and in such cases the membrana nictitans is pushed out 

 from the bulbous and extended over the cornea. The ciuestion whether 

 this condition is a form of follicular conjunctivitis or it is to be accepted 

 as a disease sui generis, we have not been able to determine fully, but we 

 know that the presence of numerous lymphatic follicles prolongs indefi- 

 nitely the course of a case of conjunctivitis. We ought, therefore, to 

 always expose the membrana nictitans by means of a pair of forceps; 

 evert the mem1)rane and examine it to see if there are any enlarged 

 follicles, or a foreign bod}^ present, especially in catarrh of the conjunctival 

 tissue. According to Frohner, 40 per cent, of all dogs are affected more 

 or less by conjunctivitis follicularis. 



Purulent Conjunctivitis; Conjunctival Blennorrhoea. 



Etiology. — It is generally admitted that this disease is due to a 

 specific infectious organism developed in the course of some epizootic 

 disease, particularly distemper, and a specific form of this disease may 

 occur as an epidemic, the cause of which up to the present time has not 

 been definitely described. It is possible to produce the same form of the 

 affection by inoculating the conjunctiva of a healthy dog with this 

 purulent material. Guilmot observed that by placing dogs in a kennel 

 which had been previously used by a dog affected with, this disease that 

 they soon became similarly affected, and it has been found to be carried 

 by the benches where dogs are exhibited. Frohner has seen it in 

 many cases of distemper, and thinks that the development of this form 

 of conjunctivitis is due in all probability to the transmission of gonor- 

 rhceal secretion from a human being placed on the conjunctiva of the 

 dog. Guilmot says that gonorrhoea! secretion of the dog itself is the 

 cause of this disease, but this assertion is combated by Moller whose 

 experiments with secretions of preputial gonorrhoea in the dog have 

 always given negative results. 



This form of conjunctivitis is marked by considerable swelling of 

 the membrane. The membrane is sometimes spotted red b3' hemorrhages; 



