262 CONTAGIOUS DISEASES. 



The paraplegia, wliicli almost invariably sets in before the 

 termination of the disease, and ■which is described by some 

 authors as its third stage, is occasionally accompanied by other 

 paralysis, such as that of the lips. 



Glanders and farcy are not unfrequent terminations. 



PKOGRESS AND DUEATION. 



The progress of the disease is slow ; it does not terminate 

 before three or four months at least, and it may extend over a 

 much longer period. An apparent recovery should always be 

 looked on with suspicion, as the affection is subject to inter- 

 missions. When the disease exists in a country, all stallions 

 presenting persistent swellings of the sheath from unknown 

 causes should be regarded as suspicious, and if in use as repro- 

 ductors, their work in that sphere should be prohibited, for, 

 although latent, the disease is none the less contagious. — 



(M. PiEYNAL.) 



Its duration is variable, extending from three to eight months, 

 and even to three years. 



A Ministerial Order in Prussia prohibits the removal or use, 

 as reproductors, of affected stallions, and in the case of recovery 

 they are not declared healthy until after the lapse of three years. 



ETIOLOGY. 



The original cause has been until now, and is likely to remain, 

 in obscurity. A great many hypotheses, however, have been 

 raised, and M. Lafosse, in his pathological treatise, gives a long 

 dissertation on the effects produced by the crossing of various 

 breeds, the change of climate necessitated for that purpose, the 

 changeable condition of the atmosphere during the period at 

 which the disease makes its appearance, which is always in 

 spring, &c. &c. These, he says, are the predisposing causes, 

 while copulation, too often repeated, by over-exciting the genital 

 organs, and perverting the secretions of the parts which become 

 primarily affected, is the exciting cause. 



Tliis theory of M. Lafosse is, however, open to grave objec- 

 tions. If it be correct, why does not the disease appear every 

 year and in every country in which the animals are exposed to 

 the same causes ? 



