504 Veterinary Medicine. 



position to fall to one side or the other. Two months later, when 

 it had greatly improved, a second inoculation of microbe y grown 

 anaerobically in bouillon and blood, caused, on the third day, a 

 severe aggravation of the lameness. 



Accesso?y Causes. Much depends on the abundance of old dried 

 grasses of the previous year in which the larval ticks may 

 hibernate. Laud that has been burnt over in winter, that is 

 cleared of brush, or in which the aftermath has been killed by 

 free salting or liming will be largely cleared of the ticks. 



Whatever disturbs or undermines the general health lays the 

 system open to the disease and many fiockmasters in tick-infested 

 districts have succeeded in greatly reducing the mortality by 

 feeding sound hay and oats in winter. Sudden changes of 

 weather have long been noticed to coincide with outbreaks of the 

 disease. A change to cold and wet is especially dangerous as 

 causing a chill and robbing the system of its tone and vigor. But 

 a sudden access of warm spring weather, especially if at the same 

 time moist, may have a decidedl)^ predisposing effect by lowering 

 the general tone. A fatal paresis common in the flocks of New 

 York, in the absence of ticks, shows a similar tendency to select 

 the atonic animal. This occurs mainly in spring, when the sheep 

 have been shut up in close confinement for weeks or months, with 

 flaccid muscles and fatty livers, and above all if they are in 

 advanced pregnancy with twin lambs, and if their fleeces are extra 

 heavy. In both affections the majority of the flock escape, while 

 those that are specially predisposed succumb. Lambs suffer most, 

 doubtless because of relative weakness, and on account of their 

 innate and unexhausted susceptibility. 



Symptoms. After an incubation varying from ten days to thirty 

 some impairment or disorder of the innervation is shown, varying 

 widely, however, in different cases. 



The two names " trembling" and " louping ill" long used by 

 shepherds as characteristic of the disease indicate spasmodic dis- 

 order of a clonic kind, the paresis which is essentially passive 

 having been very naturally overlooked, or held to be subordinate. 

 There is hyperthermia the temperature rising at times to 105 or 

 higher, and often marked hypersesthesia and excitability at the 

 outset. On approaching the patient it is very much frightened, 

 and when caught, struggles and twitches in a remarkable manner 



