Recur?-ent Ophthalmia in Solipeds. Moonblindness. 413 



1. The recrudescence of the disease after its various intermis- 

 sions, and its preference for low, damp, cloudy localities seem to 

 ally it to the malarial diseases of man. 



2. Its appearance in certain predisposed systems, whenever an 

 injury or debility of the eye seems to open the way for the ad- 

 mission of the hypothetical microbe. 



3. The increased susceptibility of the malady when the system 

 has been debilitated by disease, overwork, heating food, bad hy- 

 giene, or parasitisms, which have undermined the native power 

 of resistance. 



4. The prevalence of the affection in given localities has been 

 supposed to imply the preservation and perhaps the multiplica- 

 tion of the germ in such places. 



5. The increasing number of victims, year by year, when the 

 same regiment or stud has been kept for a number of years in the 

 same place. The theory is that with the presence of infected 

 horses the hypothetical microbes become increasingly prevalent 

 in the locality and above all, in the stables, until even the more 

 resistant subjects tend to succumb under the repeated infections. 

 Thus Ztindel says that in 1878, 700 army horses were stationed ill 

 Saarsburg, in 1879, 6 were attacked with recurrent ophthalmia, 

 and in 1880, 84 ; Hofgeismar mentions that a dragoon regiment in 

 Frankfort had 5 horses attacked in 1876, 12 in 1877, 11 in 1878, 

 14 in 1879, and 42 in 1880. We have, however, no assurance 

 that the excessive rainfall, spoiled food or other unhygienic condi- 

 tion, may not have been a potent factor in the increase. 



6. The obvious connection of certain cases of recurrent oph- 

 thalmia with a rheumatic condition suggests the probable opera- 

 tion of the same microbian cause. 



7. The success of the treatment with potassium iodide in cer- 

 tain cases. 



Up to the present ^he microbian causation of this malady cannot 

 be taken as proved, yet as a hypothesis it explains satisfactorily 

 many of the observed morbid phenomena. That there is no such 

 rapidly spreading infection, as would warrant us in listing this 

 with animal plagues, is conceded, and that constitutional condi- 

 tions have a potent influence is allowed, but that, in addition to 

 these, microbian invasion is often a means of precipitating the 

 malady is altogether probable. It may not be necessary that the 

 microbe should in every case be of the same kind, yet the addi- 



