88 PERIODIC OPHTHALMIA. 



ecchymoses. The vitreous humour assumed a deep citrine colour ; and al- 

 though as limpid and diffluent as in health, was mingled with striated obscu- 

 rites which, separated, proved to be networks of capillary vessels, red and 

 injected, and in an inflammatory condition. As yet the chrystalline had un- 

 dergone only a slight augmentation of density, with but little diminution of its 

 transparency. But the membrane lining the chambers, which contains the 

 aqueous humour, was inflamed to that degree that it exhibited a determined 

 vermilion tint, and its vessels, which were disposed like lace-work, were most 

 conspicuous. A magnifying glass discovered, in all the internal structures, 

 and especially in the lens and its capsule, multitudes of injected capillaries, 

 which, with the naked eye, would have been invisible. What, as M. Rodet 

 remarks, is well worthy of note in this case is, that at the time the animal was 

 destroyed, which was during intermission from ophthalmia, the eyes, which 

 were of their natural colour, shewed nothing beyond some slight general ob- 

 scuration, such as the state the vitreous humour exhibited might naturally be 

 supposed to have produced. 



Diagnosis. — Although there is no likelihood of a well-marked 

 case of periodic ophthalmia being mistaken for one of simple con- 

 junctival inflammation, yet do, now and then, cases occur which for 

 a time create a doubt in the mind concerning their true nature. 

 Should there he discoverable any mark of a bite or a blow, any 

 thing be found to have worked its way underneath the lid, or even 

 any catarrhal signs, any mucous or purulent secretion from the con- 

 junctiva, the case will be evident enough. But we must not set 

 down every case which is not so distinguished as periodic; for 

 though, as far as treatment is concerned, we can do no great harm 

 be the case which it may, we may thereby mislead both our 

 employers and ourselves in respect to the event. If we will but 

 wait a little — not in treating the case, but in pronouncing any de- 

 dided opinion upon it — symptoms already existing will give way, 

 or fresh ones will declare themselves, and thus all doubt will be 

 dissipated. In simple ophthalmia — unless the cornea itself receive 

 injury — rarely will the interior of the eye disclose any other alter- 

 ation than some irritability and consequent contraction of the pupil : 

 whereas, should it be the specific disease, soon there will appear 

 either some dulness or mistiness of the cornea, some effusion into the 

 chamber, or muddiness of the aqueous humour, or else some loss of 

 colour or brightness in the iris, symptoms which but too surely 

 betray its presence. Should it happen — which is not at all likely — 



