[The eye and its diseases being so concisely treated by Mr. Youatt, we are emboldened to add a more full and particular treatise on this interesting subject, couched in language the most simple, and we trust sufficiently plain to be understood by the most unscientific patron of the canine race. THE EYE AND ITS DISEASES. THE NICTITATING MEMBRANE. It is somewhat astonishing that an organ, so delicate and so much exposed as the eye of the hunting dog necessarily is, should not more frequently be attacked with disease, or suffer from the thorns, poisonous briars, and bushes that so constantly oppose their progress while in search of game. Nature, ever wise in her undertakings, while endowing this organ with extreme sensibility, also furnished it with the means of protecting itself in some measure against the many evils that so constantly threaten its destruction. The plica semilunaris, haw or nictitating membrane, though not as largely developed in the dog as in some other animals, is, nevertheless, of sufficient size to afford considerable protection to the ball of the eye, and assists materially in preventing the accumulation of seeds and other minute particles within the conjunctiva. This delicate membrane is found at the inner canthus of the eye, and can be drawn at pleasure over a portion of the globe, so as to free its surface from any foreign substances that might be upon it. Although the eye of the dog is attacked by many diseases, almost as numerous as those of the human being, still they are much less frequent and far more tractable. OPTHAMALIA--SIMPLE INFLAMMATION OF THE EYE. In its mild form this disease is frequently met with, and easily yields to the administration of the proper remedies, but when it appears as an epidemic, in a kennel, it proves more stubborn. The discharge in epidemic ophthalmia, when carried from one dog to the eyes of another, no doubt is contagious, and, therefore, it is necessary to separate dogs as much from each other as possible during any prevalent epidemic of this nature. The disease announces itself by slight redness of the conjunctiva, tenderness to light, and increased flow of the secretions. The eyeball appears retracted in its socket, and more moist and transparent than usual. The infected vessels of the conjunctiva form a species of net-work, and can be moved about with this membrane, showing that the inflammation is entirely superficial, and not penetrating the other coverings of the eye. Extravasation of blood within the conjunctiva, (bloodshot,) is also not an uncommon appearance, but is frequently the first symptom that draws our attention to the malady.