DISEASES ARISING FKOM SPECIAL INTERNAL CAUSES. 223 



and their study in the lower animals, tends to throw little 

 light on their nature, as only one form has been at all re- 

 cognised, viz., Elephantiasis. Of these diseases in man there 

 are five, viz., Lepra, Lupus, Scrofuloderma, Kelis, and Ele- 

 phantiasis. The reason why the lower animals are rarely 

 attacked by any of these disorders is perhaps to be found in 

 their being not unfrequently of syphilitic origin. Mr Eras- 

 mus Wilson says: "The cause of the present group of 

 diseases is obscure ; it is, probably, some poison present in 

 the blood, engendered by conditions either external to the 

 body, or within the economy itself. Numerous observations 

 have led me to the conclusion that lepra originates in the 

 syphilitic poison, the poison being modified by transmission 

 through one or more generations. Lupus, in some instances, 

 is clearly referable to the poison of syphilis ; in others it 

 seems to appertain to an infection equally mysterious, 

 namely, scrofula; and scrofula, I believe to derive one of its 

 sources from syphilis. Kelis is allied with scrofuloderma, 

 often making its appearance on the cicatrices of scrofulous 

 sores, or in children suffering under scrofulous affections. 

 The cause of Elephantiasis is as much a mystery, as deeply 

 plunged in obscurity at the present day, as it was before the 

 commencement of the Christian era, when it made its first 

 outbreak among the inhabitants of the banks of the Nile. 

 From Egypt it travelled through Syria to Greece; from 

 Greece it pursued a westerly direction through Europe. 

 After exhausting itself in England, it moved northward into 

 Scotland, from Scotland to the islands of Orkney and Shet- 

 land; and at the present moment, rages with severity on 

 the coasts of Norway and in Iceland." 



Though enlarged limbs in horses have been regarded as due 

 to elephantiasis, the only malady that seems to have been 

 described with any proper foundation under this head is 



