59 



the investigators have found u germ associated with the dis- 

 ease; but, if the microbe has- been cultivated on artificial 

 media, the eye disease has never been artificially transmitted 

 or produced by means of the germ. 



Willach examined 37 eyes from 24 horses and has discov- 

 ered a variety of forms and kinds of round and flat worms; 

 most of them were found in the humors and represented the 

 young stage in their development. Similar parasites were 

 also discovered in the alimentary canal, the liver and the 

 lungs. Wallach believes that these worm-like parasites mi- 

 grate from the alimentary canal during their early life — 

 chiefly by way of the blood vessels — and thus reach the eye ; 

 these migrations take place periodically or at such times 

 as the egg or young forms of the parasites reach the ali- 

 mentary canal in the food or water. This theory would, 

 of course, explain the periodic nature of the disease and 

 many other phenomena connected with it. But the worm- 

 like forms were found only in the examination of dead eyes, 

 whereas the limited number of cases and want of transmis- 

 sion or actual production of the disease by experiment will 

 not justify, beyond question, the 'far-fetched' conclusions. 



On river bottoms, on moist clay soils, on marshy grounds, 

 on moist coast lands of seas and lakes, in malarial dis- 

 tricts, this disease is said to be most prevalent. In 1875, 

 a regiment was moved from Frankfurt on the Main to Hof- 

 geismar ; at the former place moon blindness never appeared ; 

 during the first year, at the latter place, 5 cases appeared 

 among the horses of the regiment; the second year 12; 

 the third year 11; the fourth year 14, and the fifth year 

 42. The regiment that was stationed at Hofgeismar was 

 moved to Frankfurt; during the last five years of this 

 regiment at Hofgeismar there were 130 cases of periodic 

 opthalmia, and during the first five years at Frankfurt not a 

 single case appeared. Hofgeismar, Saarburg, St. Avoid and 

 other places in Germany seem to be peculiarly adapted, by 



