GUTTA SERENA. 167 



a cataract in the right eye, of the size of a coriander seed. He advised the owner 

 to get rid of her, thinking that she would go blind ; but, being a useful animal, 

 he kept her. In August 1833, Mr. Cartwright saw her again. The cataract 

 had disappeared and the eyes were perfect*. 



That excellent veterinarian, Mr. Percivall, had a somewhat similar case. 

 A gentleman brought a horse one morning to the hospital, in consequence of 

 its having fallen in his way to town, and grazed his eyebrow. On examining 

 him carefully, the cornea was partially nebulous, and a cataract was plainly 

 visible. Neither of these defects was sufficient to attract the notice of any 

 unprofessional observer, and both were unconnected with the slight bruise pro- 

 duced by the fall. The owner was told that the corneal opacity might possibly 

 be removed ; but as for the cataract he might regard this as beyond the reach 

 of medicine. He returned with his horse on the fifth day, saying that the 

 physic had operated well, and that he thought the eye was as clear as ever. 

 Mr. Percivall examined the eye, and could discover no relic either of the 

 corneal opacity or of the cataract. 



The opinion respecting cataract is therefore essentially modified. It is not 

 necessarily the result of previous inflammation, although hi the great majority 

 of cases it is so, nor does it always lead to blindness. Still it is a serious thing 

 at all times, and, although existing in the minutest degree, it is unsoundness, and 

 very materially lessens the value of the horse. 



" Were I asked," says Mr. Percivall, " how the practitioner could best dis- 

 tinguish a cataract of the above description from that which is of ordinary 

 occurrence, and known by us all to constitute the common termination of perio- 

 dical ophthalmia, I should say that the unusually lucid and healthy aspect which 

 every other part of the eye presents is our best diagnostic sign ; the slightest 

 indication, however, or the slightest suspicion of prior or present inflammation, 

 being a reason for coming to a different conclusion. As to the period of time 

 a cataract of this species, supposing it to be membranous, would require foi 

 its- formation, I should apprehend that its production might be, as its disappear- 

 ance often would seem to be, the work of a very short interval, perhaps not more 

 than five or six days." As to the cause and treatment of it, we are at present 

 completely in the dark. If it does not soon disappear, the hydriodate of 

 potash administered internally might offer the best prospect of success. 



OUTTA SERENA. 



Another species of blindness, and of which mention was made when describing 

 the retina, is Gutta Serena, commonly called glass eye. The pupil is more 

 than usually dilated : it is immovable, and bright, and glassy. This is palsy of 

 the optic nerve, or its expansion, the retina ; and is usually produced by deter- 

 mination of blood to the head. We have described it as a consequence of 

 staggers. So much pressure has been occasioned on the base of the brain, that 

 the nerve has been injured, and its function destroyed. The treatment of 

 Gutta Serena is quite as difficult as that of cataract. We have heard of suc- 

 cessful cases, but we never saw one ; nor should we be disposed to incur much 

 expense in endeavouring to accomplish impossibilities. Reasoning from the 

 cause of the disease, we should bleed and physic, and administer the strych- 

 nine in doses, commencing at half a grain, and not exceeding two grains, 

 morning and night very carefully watching it. If we succeed, it must be 

 by constitutional treatment. As to local treatment, the seat of disease is out of 

 our reach. 



* Veterinarian, vol. vii. p. 44. 



