448 



SPIRILLUM CHOLERA ASIATICS. 



external 

 influences. 



Results of 



practical 



experience. 



Contagious 

 cases of 

 cholera. 



disease, whether it be that in this case there is a want 

 of resistance on the part of the whole body, or some 

 weakening of the digestive organs. 



Hence, on the whole, the occurrence of infection 

 depends to a great extent on external influences, which 

 either favour its development or the reverse. The 

 number of sources of infection is sometimes larger, 

 sometimes smaller, the modes of transport are some- 

 times numerous, sometimes few, and may ultimately be 

 entirely absent ; and it is possible that if the infective 

 material enters the body it may pass through it without 

 setting up disease, thanks to the protective arrangements 

 present. 



The question arises whether these views deduced 

 from the chief facts which have been ascertained as to 

 the biological characters of the comma bacillus coincide 

 with the results which have been made out empyrically 

 as to the mode of spread of cholera. Numerous facts 

 have rendered it absolutely certain that cholera can be 

 carried by contagion, the virus being transmitted from 

 the sick to the healthy. Typical cases of contagion 

 occur in almost every epidemic ; they are most definite 

 when the epidemic is only commencing and has not yet 

 spread widely, while at the height of the epidemic, or in 

 an endemic area, it is impossible to trace the origin of 

 the individual cases. As a classical example of un- 

 doubted transmission in this way we may mention the 

 case observed by Virchow in the department of the 

 Charite Hospital in Berlin, set apart for prisoners, where 

 three individuals to whom the nursing of a cholera 

 patient was entrusted became ill of cholera after a few 

 days, while no case of cholera occurred among any of 

 the other healthy or sick inhabitants of the hospital.* 

 Many well-observed epidemics in ships and houses, in 

 which the reproduction and the transmission of the 

 disease may be distinctly followed through a number of 

 patients one after the other, can also only be explained by 

 contagion. But for a long time the conclusion drawn 



* Weissbach, Virckow's Arch., vol. 55, P. 249. Virchow in th 

 Verhandlungen der Chohraconferenz., 1885. 



