192 THE CONTAGIOUS TYPHUS 



at present to the consideration of its pathogenia 

 and its nature. Only, the limits of this book 

 will not admit of a complete discussion of 

 every point of this important question of 

 pathology ; for if we desired to show in 

 what respect the typhus differs from, and in 

 what respect it resembles, such and such a 

 morbid entity, febrile, infectious and con- 

 tagious like it, such a dissertation would 

 require a whole volume for itself; we are 

 therefore obliged to keep within certain limits. 

 Like every watchful physician who has 

 applied himself to the study of comparative 

 pathology, we entertained our own precon- 

 ceived opinions as to the nature of this Cattle 

 Plague. Arguing a priori from what we knew, 

 from the laws of the pathogenia of those 

 exanthematic diseases which we have alluded 

 to in a former chapter ; from the identity of 

 variola in various animals ; from the pre- 

 ventive treatment to which this identity has 

 led ; believing that animals and man have each 

 their typhoid fever, as they have their variola 

 or small-pox ; considering with the Ecole de 

 Tours, typhoid fever as a variola of the intes- 

 tinal mucous membrane, and having proposed, 



