CHAPTER XXIV 

 SPIRILLACE^ AND THE DISEASES CAUSED' BY THEM 



Spirillum Rubrum. — Esmarch discovered this organism in 

 the body of a dead mouse. It is of chief interest as a harmless 

 example of spiral bacterium for class study. It grows rather 

 slowly at room temperature without liquefying gelatin. A dull 

 red pigment, insoluble in water, is produced even in the absence 

 of oxygen. Growth occurs at 37° and also in the refrigerator at 

 5° to 10" C. When grown at temperatures above 20° C. the 

 organism is a relatively short, slightly bent rod ' and its spiral 

 nature is not very evident. At 10° C. beautiful long spirals are 

 produced in broth cultures. It is actively motile. 



Spirillum Cholerae (Vibrio Cholerae). — Koch in 1883 discovered 

 this organism in the intestinal discharges of patients suffering 

 from Asiatic cholera, and continuing his studies in India in the 

 same year established this organism as the proba.ble cause of 

 cholera. It occurs in the intestinal contents and feces of cholera 

 patients, often in great abundance, rarely in the feces of healthy 

 persons, and has been found at times in surface waters, and in 

 drinking water during epidemics of cholera. 



Sp. cholercB is a curved cylinder about 0.411 in thickness and 

 i.S/i in length. In older cultures in broth long spiral forms occur. 

 There is considerable variation in shape in cultures older than 

 48 hours. The organism is actively motile and possesses a single 

 flagellum at one end. Those short spirals showing more than 

 one flagellum are not to be regarded as true cholera germs. Spores 

 have not been observed. The spirillum stains readily and is 

 Gram-negative. 



It grows well and rapidly on ordinary media. The reaction 

 needs to be distinctly alkaline to litmus as the organism is very 



