398 BACTERIOLOGY. 



still much more marked than that seen as a result of 

 the growth of Koch's spirillum. Indeed, under these 

 circumstances there is no similarity whatever between 

 the growth of the two organisms (see a, h, c, d, Fig. 11, 

 and compare these with corresponding cuts in Fig, 74). 



It is customary to see scattered through the cloudy 

 liquefied gelatin, ragged, more or less dense masses, 

 fragments of the colony proper. 



On nutrient agar-agar there is nothing particularly 

 characteristic about its growth, appearing only as a 

 moist, grayish or yellowish-gray deposit. 



On potato, after forty-eight to seventy-two hours, 

 there appears a pale, yellowish-gray deposit; this is 

 moist, glazed, and marked by lobulations, and is sur- 

 rounded by an irregular, colorless zone of growth that 

 is much less moist than that forming the central area. 

 It grows well on potato at the ordinary temperature of 

 the room. 



It causes liquefaction of solidified blood-serum and 

 of coagulated egg-albumin. 



In milk to which neutral litmus tincture has been 

 added the blue color takes on a pink tinge in from two 

 to three days at 37° to 38° C. 



It does not form indol nor does it cause fermentation 

 of glucose. 



In peptone solution containing rosolic acid the color 

 is somewhat deepened after four or five days at 37° C. 



Experiments upon Animals. — By ordinary meth- 

 ods of inoculation this organism is without pathogenic 

 properties. Injections, subcutaneous and intravascular 

 and directly into the stomach, give negative results. 

 When introduced into the stomach of guinea-pigs by 

 the method employed by Koch in his cholera experi- 



