Etiology. 887 



of the disease. Studies on the nature of the disease were especially 

 carried out by Bollinger (1877), Frohner (1884), McFadyean (1888), 

 Lucet (1889), W. Eber (1892), Dieckerhoff (1895), Lignieres (1898), 

 Cadeac (1899), Hink (1901), and Schlegel (1906). Schlegel at first 

 strictly separated the affection from enzootic spinal- meningitis 

 (Meningomyelitis haemorrhagica), later however he considered them 

 as identical affections. Furthermore paralytic hemoglobinuria has 

 formerly frequently been confused with enzootic spinal meningitis. 

 Johne (1879) described the disease in a zebra. 



Etiology. The observations of many years up to the present 

 time have proved beyond a doubt that the development of the 

 disease is favored by the cooperation of certain predisposing 

 causes. The most conspicuous influence is the method of keeping 

 the horses, inasmuch as the disease usually appears after a 

 long rest with rich feeding at the same time. Accordingly it 

 occurs especially after holidays of several days ' duration. How- 

 ever, exceptions are not at all rare, as occasionally resting 

 horses may become affected even in the stables, or horses that 

 are hitched up every day may become affected during work, 

 and again poorly nourished or even starving animals may be- 

 come attacked by the disease (Hauptmann). 



Brun observed in a large stable, in which the horses were not worked for 

 sixteen days and where the daily exercising was impossible, that eight cases 

 occurred inside of three days, while among the horses of another stable in which 

 the animals were exercised every day only one, and that a slight case, was noted. 



The influence of breed is sufficiently proved by general 

 observations, in that horses of draft breeds become affected 

 most frequently, while the disease appears more rarely in ani- 

 mals of the finer breeds. Among common Hungarian horses, 

 as well as in the more hardened horses of poor men, the dis- 

 ease seldom occurs. 



According to the tabulated statistics of Adam, among 63 affected horses 

 31% were heavy draft animals, 36% improved breeds of country horses, 20% 

 wagon horses, and 9% belonged to higher breeds. Immediately before the affec- 

 tion five horses were stabled for one day, 21 horses for two days, 11 horses for 

 3 days, 9 horses for 4-5 days, four horses for 5-8 days. Out of 352 cases observed 

 by Sohindelka & Hofling, 46% belonged to heavy draft, 19% of medium weight 

 animals, and 35% to light weight breeds. 



Horses usually become affected between the ages of five and 

 eight years, much more rarely at earlier or later ages. 

 (Razsovits and Hutyra & Marek each observed the disease in 

 a foal of 1% years of age ; according to Kleinpaul even sucking 

 colts are supposed to be susceptible?) 



Excessive exertions may produce the disease even without 

 a previous rest; besides cases are not infrequent in which the 

 disease develops after parturition or in horses which have 

 struggled considerably during painful operations (Bergstrand, 

 Frohner, Leipziger, Dages, Pr. Mil. Vb.). Likewise horses 



