SEVENTH ANNUAL YEAR BOOK— PART X. 481 



pure breeds of coarse-wooled shee]) and the grades of lx)tli of these breeds 

 of animals are by no means exempt. In the latter animals, however, the 

 disease runs a milder course, and is more amenable to treatment than in 

 the case of the fine-wooled sheep. Sex or age does not appear to have 

 any important influence on the susceptibility of the animals, as the 

 disease manifests itself quite generally in the flock, attacking alike male 

 and female, lambs, yearlings and aged sheep. 



INFECTIVE CHARACTER. 



Some of the early writers seem to have been convinced that this disease 

 was in no degree contagious, but at a later period many investigators 

 opposed this opinion and strongly maintained that it spread from sheep 

 to sheep by means of some contaminating agent which exuded from the 

 erosions upon the affected feet. 



In opposition to these statements many veterinary writers were posi- 

 tive in their declarations that the disease was never caused otherwise 

 than by pasturing on low, swampy lands, or as a result of overgrown toes 

 or by other conditions due to faulty care and surroundings. 



But while the majority of writers seem to have denied that the disease 

 possessed any contagious properties, there remained a very lively minority 

 who entered a most vigorous protest against this view of its character, 

 and who cited instance after instance in support of their claim that it was 

 strictly of a contagious nature. They mentioned cases in which affected 

 sheep had been brought from a distance and placed in flocks that had been 

 sound and healthy for years, with the result that a portion of the flock 

 scon became affected; also a case in which healthy and diseased flocks 

 pastured in adjoining fields without any transmission of the trouble 

 until a time when two or three of the sound animals jumped the dividing 

 fence and grazed for the remainder of the day with the contaminated 

 flock, with the result that they promptly contracted foot-rot. These writ- 

 ers recorded the infection of sound flocks as the result of their having 

 been driven over roads which diseased sheep had traversed but a short 

 time previously. Reports were made of test lots of sheep that were 

 pastured for months on swampy and muddy lands without spontaneous 

 development of foot-rot, which promptly became affected, however, on thejr 

 removal from these pastures when inoculated on the skin ; between the 

 claws of their feet with discharge from an affected foot. , They men- 

 tioned several attempts at experimental inoculation with bits ,df diseased 

 tissue, or with some of the moist excretions from ;an affeiQte^ foot,, which; 

 usually favored the investigator with successful termjnationsj 



One of the best of these experiments was reported by Favre In .1822. 

 He simply moistened the skin between the claws of ,32 ieaithy sheep 

 with matter obtained from diseased feet, with the result tha,t., 21 ,ftf 

 them contracted the disease in consequence of this slight exposure. 



Another convincing argument in favor of:ithe dependence . qf tpctt-Tf^t 

 on a specific cause is found in the fact th^-t ypung ^rnhs yeaned .;% 

 affected ewes have been known to show unniistal^3(^(^, ,^y;m^toms of 'tlip 

 disease as early as the sixth day after birth, and as this has, pccuyr^ji 

 in flocks that have been closely stabled there remains no possibility that 



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