NATURE AND AFFINITIES. 311 



frappante. Mais il s'en distingue ^noriuement par I'absence de la 

 contagiosite atmosph^rique.'' 



Human small-pox belongs to a different group of diseases, and 

 has affinities rather with small-pox of sheep and cattle plague, 

 diseases which are not only inoculable, but highly infectious. Human 

 small-pox is an infectious disease characterised by sudden and severe 

 fever, followed after forty-eight hours by a generalised eruption ; horse- 

 pox commences as a local affection, and constitutional symptoms 

 follow. Auzias Turenne, guided by analogy, described the general- 

 ised eruptions following "grease" or horse-pox as greasides {'^comme 

 on dit syphilides"). 



Horse-pox and human syphilis are absolutely distinct diseases ; 

 and there is no more ground for believing that horse-pox originates 

 in humaa syphilis than there is for accepting the theory that it arises 

 from grooms suffering from small-pox. Syphilis artificially inocu- 

 lated on the human subject only resembles the casual or intentional 

 inoculation of virulent horse-pox. The stages of papulation, vesicu- 

 lation, ulceration, scabbing, and the formation of a permanent scar, 

 occur in inoculated syphihs, and if we examine Ricord's illustrations 

 and study the experiments of Auzias Turenne, we cannot fail to 

 be struck with the remarkable similarity to the results obtained and 

 depicted by Jenner. 



But in order to follow the argument of Auzias Turenne we 

 must study the natural and casual horse-pox. And if we are not 

 familiar with what has been written on this subject, and if we 

 restrict our knowledge to the artificially cultivated horse-pox, we 

 shall fail to recognise the disease when we meet with it, and we shall 

 be liable to attribute the results of the full effect of the virus to 

 ' accidental contamination. 



Another question of very great interest is the relation of horse- 

 pox to cow-pox. Jenner first of all propounded the theory that all 

 cow-pox arose from horse-pox, or as he termed it " the grease," and 

 thus cow-pox and horse-pox were manifestations of the same disease. 

 But it was established that cow-pox also arose quite independently 

 of horse-pox, and Jenner was led to distinguish between cow-pox, 

 a disease peculiar to the cow, and the eruptive affection transmitted 

 to the cow from the horse, which farmei-s and others, by a strange 

 perversion of terms, called the cow-pox. Whether the eruption of 

 cow-pox can be distinguished from the eruption of horse-pox com- 

 municated to the cow, and whether cow-pox and horse-pox are 

 identical, or only analogous, are questions which call for further 

 investigation. 



