CHAPTER IX. 



Cholera (continued), 



Pettenkofer's researches — Saprophytic and Parasitic Stages of Cholera 

 Bacillus — Temperature Conditions — Relation to Epidemics — Moisture 

 — Ground Water — Flushing — Cholera in Shanghai Endemic but 

 Intermittent — Cholera Endemic at the Mouth of the Ganges — Vitality 

 of Cholera in Old Cultures — Relation of this to Quiescent Periods 

 during Parts of the Year — Gastro-intestinal Irritations prepare for 

 Cholera — Chinese Vegetables — Cholera Poison Formed in the Intestine 

 absorbed into Body — Inoculation against Cholera — Gamaleia's Experi- 

 ments — Germicides useful in attacking the Cholera Bacilli — Water 

 Supply, Pilgrimages, Feasts predisposing to Cholera —Quarantine 

 except in Harbours Useless — Time and Place Dispositions. 



Pettenkofer's indefatigable researches on the relation of 

 ground water and the drying zone to cholera epidemics have 

 thrown much light on many obscure points, and have opened 

 up the way for further work. He holds that the increase of 

 cholera is due entirely to the increase of the " drying zone " 

 near the surface of the soil — z'.e., the lowering of the level of 

 the " ground water," and that the rise and fall in the level of 

 this ground water is the principal factor in the production of 

 conditions necessary for the outbreak of epidemics of various 

 kinds. On these grounds he has itaken up a very strong 

 position against the spread of cholera directly from patient 

 to patient. There can be little doubt that many of Petten- 

 kofer's observations are entirely in accordance with this view, 

 but equally can there be little doubt that all his interpreta- 

 tions of the facts he has collected are not entirely accurate, 

 although, as Hueppe points out. Wood's observations offer 

 solutions of questions that have hitherto been unanswerable. 

 The instances are almost innumerable in which there has been 

 a most remarkable immunity against the passage of cholera 

 from individual to individual ; where the dead bodies have 

 been buried immediately the disease has afterwards occurred, 

 not in those who have had to carry out the actual burying of 



