SPIRILLUM CHOLERA ASIATICS. 423 



of bacterium in any process does not at the same time 

 imply an etiological relation between the two. 



The second hypothesis of the occurrence of comma 

 bacilli in cholera is still more unlikely, namely, that 

 Koch's comma bacilli have been developed as the result 

 of the influence of the cholera disease from other species 

 of vibrio which are normally present in the intestine. 

 Such a transformation of one species of bacteria into 

 another which is well characterised, and which has 

 remained unaltered in its properties for years when 

 cultivated under a great variety of conditions, has as 

 yet never been observed, and certainly not in such a 

 regularly recurring and exclusive manner, under the 

 influence of a definite morbid process. Such an hypo- 

 thesis is without any foundation, and directly contradicts 

 all the facts which have been obtained as the result of 

 observation and experiment. 



Hence in the present state of our knowledge we can AS a conse- 

 come to no other logical conclusion than that Koch's ^TsUoo^on 

 comma bacilli are the cause of cholera. With the same the comma 

 right with which we infer the etiological significance of cause of 

 the spirilla of relapsing fever, of the leprosy bacilli, of cholera - 

 typhoid bacilli, &c., from their constant and exclusive 

 occurrence in these diseases ; with the same right 

 with which we must look on the syphilis bacilli as the 

 cause of the disease as soon as their constant and ex- 

 clusive occurrence in syphilitic new formations has been 

 certainly proved, we must also recognise that the comma 

 bacilli, on account of the proof of their constant and 

 exclusive presence, are the only and sufficient cause of 

 Asiatic cholera. 



The following facts have up to the present time been Morphological 

 ascertained with regard to the morphological and bio- the comma f 

 logical characters of Koch's comma bacilli : bacilli. 



The comma bacilli usually present the appearance of 

 short curved rods, which, under certain circumstances 

 remain in connection with each other, and form long 



