92 PERIODIC OPHTHALMIA. 



breeding from either horse or mare that had gone blind : they said, 

 * it was ahiiost sure to run in the stock.' I Avas laughed at, 

 I remember, for giving utterance to such a vulgar and obsolete 

 crotchet. I care not," continues Mr. C, " whether this be called 

 hereditary disease or only an original predisposition : it amounts 

 to just the same thing; and I venture to affirm, that this is by far 

 the most frequent origin of the periodical oj)hthalmia in horses. 

 But, while I assert this, I am ready to admit that it also arises 

 from a variety of other causes, quite adventitious and unconnected 

 with this source." 



Mr. Spooner — at the Veterinary College — is so warm an ad- 

 vocate for hereditariness, that he proposes to call the disease 

 •* hereditary ophthalmia." A gentleman stated to Mr. S. that the 

 stock of a certain stallion had all contracted the disease, though the 

 horse himself had never been known to suffer from it. 



As OTHER Causes — lunar influence having been abandoned — 

 a variety of agencies have been adduced, and had their supporters. 

 Digestion has been accused of causing it. Marshy pastures, such 

 as generate miasmata, to which the eyes become exposed, are said 

 to produce it ; while other pastures, from their fattening qualities, 

 tend to the same result. Chabert thinks that using horses too 

 voung brings it on. Some French veterinarians have referred it 

 to the cutting of the teeth, and the mastication of hard provender 

 at the time ; and upon this Dupuy seems to have founded his 

 opinion, that the disease in the eyes arises from the irritation 

 caused by the compression of the molar teeth upon the fifth pair of 

 nerves ; a circumstance, he informs us, he has proved by anatomy 

 to be peculiar to horses. And, in confirmation of his theory, he 

 adduces the experimental results of section of the fifth nerve, which 

 he finds, as regards the eye, to be, obscuration of the cornea, 

 together with inflammation of the conjunctiva, iris, &c., and all 

 the consequences thereof. Here is a strange and unlooked-for 

 result, and a phenomenon altogether that calls for serious consider- 

 ation on our part. We cannot view it as the chief cause of oph- 

 thalmia, because there are facts strongly militating against it : at 

 the same time we would not deny all influence to it. 



Professor Sewell — as we learn from the Reports of the 



