DEMONSTRATION OF CHOLERA VIBRIO. 371 



Vibrio luminosus (Beij.) L. and N. (Photobacterium luminosum 

 Beijer.), obtained from the North Sea. It is very closely related to 

 the Vibrio indicus, according to Beijerinck. It liquefies vigorously 

 and presents vibrios and spirilla. According to Beijerinck, it also is 

 photogenic without the addition of sugar. Slight addition of sugar 

 favors photogenesis; a little more (\% or more of dextrose) inhibits it. 



Vibrio balticus (Beij.) L. and N. (Phot, balticum Beijer., C. B. 

 vm, 616). "Native phosphorescent bacillus" Fischer (C. B. in, 

 105), from the Baltic Sea. Described by Fischer as very similar to the 

 Vibrio indicus. Light, bluish-white. In the description of the 

 microscopic character and the appearance of the cultures, Fischer him- 

 self often compares it to the Vibrio cholerse. Minimum, below 5. 

 It produces light, according to Beijerinck, only upon nutrient media 

 which contain sugar. It bears very well a large proportion of sugar 

 (3%-5$> of cane-sugar). The freshly isolated cultures liquefied very 

 little. Beijerinck finally obtained very vigorously liquefying cultures 

 by longer cultivation on gelatin. It does not ferment sugar. 



Vibrio Fischeri (Beij.) L. and N. (Photob. Fischeri, Beijerinck; 

 C. B. vm, 616). According to Fischer, it stands very close to the 

 Vibrio balticus. When freshly isolated, it liquefied very vigorously, 

 and gradually almost completely lost this property. Traces of cane- 

 sugar favor the photogenesis ; 0.5^> or more lessens it. It does not 

 ferment sugar. 



Vibrio terrigenus. Gunther (C. B. xvi, 746). 



Does not liquefy gelatin at all, forms a delicate pellicle upon gela- 

 tin. It is interesting, from the standpoint of classification, that it 

 possesses either a single flagellum or a bunch of flagella at each end. 

 Gelatin colonies are smooth-edged and structureless; the superficial 

 ones form little heaps. Older deep colonies are brownish and studded. 

 It produces a good yellowish-white growth upon potato. Sugar is not 

 fermented, milk not coagulated. It is not pathogenic for animals, 

 and is an obligate aerobe. Obtained from Berlin soil. The Vibrio 

 saprophiles a, /?, y Weibel appear to be similar (C. B. iv, 225, 257, 

 289). 



Special Methods for the Demonstration of the Cholera 



Vibrio. 



The examination should usually be completed in twenty-four to 

 thirty -six hours. 



A. In the evacuations of cases of cholera or suspected cholera. 1 



1. Microscopic preparation (usually from a flake of mucus!): The 

 presence of abundant vibrios (especially if arranged parallelly like 



1 The demonstration is conducted in the same manner in the case of 

 milk and other foods, soiled linen, old dried laboratory cultures, etc. 

 Here often the direct microscopic observation can be omitted. 



