226 A MANUAL OF BACTERIOLOGY 



whole of Europe.' The native habitat or the 

 endemic area of this terrible disease is in India 

 especially in the delta of the Ganges. ' It can be 

 readily understood, after the fearful ravages which 

 it made in places in which it was not actually 

 endemic, and after it had decimated the population 

 in certain parts of India, in Egypt, in the low-lying 

 portions of Persia, and Asia Minor, and in Europe, 

 that many observers should be anxious to find out 

 the ultimate cause of the disease ; and as early as 

 1848 Virchow, and in 1849 Pouchet, Brittan, and 

 Swaine found numbers of vibriones in the dis- 

 charges of choleraic patients, without, however, 

 being able to assign to them or prove for them any 

 specific rdle in the causation of the disease.' x Since 

 1848, many scientists have been at work trying to 

 establish a specific cause of cholera ; but it was not 

 until 1884 that Dr. R Koch 2 discovered the comma 

 bacillus in choleraic dejecta, etc. Although many 

 distinguished pathologists have not accepted Koch's 

 evidence of the bacillary nature of Asiatic cholera, 

 there can be no doubt, after the important and 

 extensive researches of Drs. Macleod and Milles, 3 

 that the comma bacillus of Koch is the cause 

 (directly or indirectly) of Asiatic cholera. 



The comma bacillus or Spirillum cholerce Asiaticce 

 measures from 1'5 to 2-5 //, long and O6 p broad 

 (Fig. 33, 3). It occurs singly, in pairs often S~ 

 shaped, in filaments which are screw-shaped, and 



1 Woodhead's Bacteria and their Products, p. 151 (W. Scott). 



2 Deutsch. Med. Woch., 1884; Berlin Klin. Woch., 1885. 



s Proceedings of Royal Society of Edinburgh, vol. xvi. p. 18. 



