CHOLERA. 631 



The constant periodicity of cholera in Calcutta or Madras can not thus 

 be cleared up. In the same way it is impossible to understand on this 

 doctrine how it is that the hot, dry season, which must be destructive 

 to the bacilli, is the period during which cholera is most prevalent, 

 and how it is that in the hot and wet season, which is favorable to the 

 growth of bacilli, cholera is at its lowest ebb. That cholera and ty- 

 phoid fever are more flourishing when the ground-water is sinking 

 than when it is rising has been explained by the drinking-water theo- 

 rists on the view that when the ground-water is falling it becomes 

 more concentrated, thicker, and therefore more dangerous. Now, the 

 prolonged researches of Wagner, Aubry, and Port have proved the 

 direct opposite. When the ground-water is low it is always purer 

 than when high. Dr. Port has studied for a number of years the state 

 of the water in the garrisons of Munich, with a view of watching its 

 relations with the movement of typhoid fever, and he has found that 

 when the water began to be impure then a falling off in the disease 

 might be predicted. Why this should be do has received an experi- 

 mental explanation from Dr. Franz Hoffmann. Great and numerous 

 are the objections to the explanation of the local disposition to cholera 

 by means of the drinking-water doctrine. Lyons was until the year 

 1858 supplied with water from superficial wells. The analyses of the 

 waters from a number of the wells prior to the introduction of a better 

 supply would astonish any one. The contagionists get out of their dif- 

 ficulties by merely asserting that though it is always the water which 

 transmits cholera, yet there are a thousand ways in which this may be 

 accomplished. But we have already shown that severe epidemics may 

 occur without drinking-water being implicated, and consequently it is 

 questionable whether, in those epidemics where the water may have 

 been a factor, other causes did not play a more important part in the 

 development of the malady. It is for the contagionists to i)rove why 

 the infection by drinking-water can only be verified in certain cases. 

 The most popular argument of the contagionists is the proposition that 

 cholera spreads by human intercourse, a fact which I unhesitatingly 

 accept. But the interpretation which the contagionists put upon the 

 fact is nullified by the fact itself, as is shown by a closer study of all 

 the influences of intercommunication, whether by land or sea. 



In many regions there are main streets running in watered valleys 

 in the direction of the stream, and yet other principal streets having a 

 direction at right angles to that of the stream. In these streets, as is 

 well known, at short intervals there exist sites which may be dotted 

 on a special map where the fi-equency of cholera may be investigated, 

 just as I had done for the epidemic of 1854 in Bavaria. It transpired 

 that the sites of the epidemic preferred to spread in the length of 

 those streets in the valleys which followed the course of the stream. 

 When, however, one investigated the epidemic spots in streets which 

 cross valleys between which hills or table-lands lie, it was found that 



