528 SEDG^y^CK and wixslow. — bacillus of typhoid fever. 
1 
Marchisoii pointed out that a " great increase of enteric fever in the autumn 
monllis was observed in cacli of the twentj-three years, with one noteworthy 
exception (18G0)." Tie also noted that the autumnal increase did not subside 
iiainedlately on the advent of winter, and concluded that ^^ it would seem as if the 
cause of the disease were only exaggerated or called into action by the protracted 
heat of summer and autumn, and that it required the protracted cold of winter and 
ppring to impair its activity or to destroy it." 
He rpioted numerous observers, Todd and Burne in England, Stewart in Scotland, 
Luinbard and ItilHet and Barthez in Switzerland, Piedvache, de Claubry and Druher in 
France, Forget and Quincke in Germany, and Bartlett, AYood, and Flint in the United 
Stales, as recording the autumnal character of the disease. Finally he added, " Not 
only does enteric fe 
but it has been found to be unusuallv 
prevalent after summers remarkable for their dryness and high temperature, and to 
be unusually rare in sunnners and autumns which are cold and wet." The references 
to the early authorities quoted by Murchison will be found in his elaborate 
bibliography. 
Liebenneister also had a clear conception of the possible effect of temperature 
upon tlie prevalence of typhoid fever. In his article on typhoid fever in Zlemssen s 
Cyclopedia,^^'^) he plotted the monthly deaths in Berlin and hospital admissions in 
London and Basle, compared with curves of the monthly variations in temperature, 
and commented on the results as follows: "The Lreneral bearing of these curves is 
^^iAV^iCli IJ^<*Llllg 
evident. The curves representing the frequency of typhoid correspond to the 
curves of average temperature, only with this difference. The different points of the 
typhoid curve follow those of the temperature curve by an interval of some months. 
The minimum of temperature falls in January, that of typhoid in February or April; 
the maximum of temperature flills in July, that of typhoid in September and October. 
It appears, therefore, that the development and spread of typhoid fever is favored 
the high sunnner temperature and checked by the low winter temperature. The 
nitcrval of two or three months between the temperature and the typhoid curves 
correspond to the time which is necessary for the changes of temperature to penetrate 
to the places where the typhoid poison is elaborated, for the development of the 
poiso 
without the human body, for the period of incubation, and for the time 
between the commencement of the attack and that of the patient's admission to the 
hospital, or that of his death." 
Coir-ot,''^) in France, about the same time, noted that the month of October always 
showed a maximum of typhoid, that the intensity then diminished till spring, and 
