§ xiii.J Asiatic cholera. 163 



rods was naturally compared by Koch to that of a comma, and 

 he therefore called them comma-rods, comma-bacilli. In good 

 nutrient solutions, such as meat-broth, and in old gelatine 

 cultures, the segments more frequently remain united together 

 into long unbroken and apparently unsegmented spirals. In 

 both forms the Spirillum has the power of movement, the single 

 rods being more active than the longer spiral filaments, especially 

 when they have grown in old gelatine-cultures. 



Hueppe has observed in old cultures a further phenomenon, 

 which must be termed spore-formation, — the formation in fact 

 of arthrospores. The spiral filaments, beginning at intercalary 

 spots, divide for a certain distance into spherical segments, 

 which are a little thicker than the vegetating cells, are more 

 highly refringent, and are separated or held together by thiimer 

 gelatinous envelopes. In this form they do not divide, but if 

 supplied with fresh nutriment they may at a later period 

 develope again into comma-rods, and by so doing they justify 

 their claim to be called spores. Spores of this kind appear to 

 have been seen, but not rightly understood, by former ob- 

 servers. They are quite distinct from the formations described 

 by Ferran. These are to be seen when spiral filaments in old 

 cultures swell up irregularly and shapelessly, or form round 

 bladders at their extremities, and then, as later observers have 

 unanimously declared, die off and disappear. They are con- 

 nected, therefore, simply with the retrogressive or involution- 

 forms common among Bacteria, and noticed above on page 10. 

 Ferran's sensational descriptions of these objects are inconceiv- 

 able to every sensible man with any pretension to a scientific 

 education. They have no other significance than that of a 

 warning example of the follies a man may commit, when he is 

 bent on making faulty observations seem important to himself 

 and others by the use of names and technical expressions which 

 he does not understand. 



With respect to the biological characters of the Spirillum of 

 cholera, it is no longer needftil from the accounts which we 



M 2 



