cxlii THE BEGINNINGS OF LIFE. 



appear to be capable of generating the poison de novo! 

 After alluding to the mode in which epidemics commence, 

 Dr. Murchison adds : ' I would allude in particular to an 

 epidemic of true typhus which occurred in 1843, at Broulhac, 

 an elevated village in the Canton de Puy, in France. 

 Most of the inhabitants were in a state bordering on starva- 

 tion ; and the first cases were traced to a house where there 

 was overcrowding and no ventilation. It is impossible to 

 conceive that the disease was imported, inasmuch as true 

 typhus was not prevalent at the time in any other part of 

 France V With regard to relapsing fever, on the other 

 hand, it has been shown 2 that this (which is essentially the 

 famine fever) is more dependent upon extreme starvation 

 than upon overcrowding. Although it is not always easy to 

 separate these two causes, it has been ascertained that in 

 mixed epidemics of typhus and relapsing fever, relapsing 

 fever is most prevalent towards the commencement, and 

 typhus towards th<e close, of the outbreak. Then, again, we 

 know that relapsing fever is not confined to large towns, but 

 that it also decimates the starving inhabitants of country 

 places. 



1 Dr. Murchison very aptly remarks : ' It has been the custom with 

 many writers to refer epidemics of typhus to some subtle " epidemic in- 

 fluence ;" and thus when a failure of the crops has been followed by 

 typhus, both of these disasters have been ascribed to a common atmo- 

 spheric cause. But of such atmospheric influences, capable of producing 

 typhus, we know nothing ; their very existence is doubtful, and the 

 employment of the term has too often had the effect of cloaking human 

 ignorance, or of stifling the search after truth. If typhus be due to any 

 " epidemic influence," why does this influence select large towns and 

 spare the country districts ? Why does it fall upon large towns in exact 

 proportion to the degree of privation and overcrowding among the poor ?' 

 (loc. cit.) Still, although the prevalence of typhus fever may be in great 

 part accounted for without resorting to unknown ' epidemic influences,' 

 it must not be supposed that there are no unknown cosmical influences 

 which have to do with the outbreak and spread of various epidemic 

 diseases. Let us rather admit that which seems so probable, and live 

 in the hope that we may one day ascertain more concerning their nature. 



2 See Dr. Murchison's 'Continued Fevers of Great Britain.' 



