SPIRILLUM TYROGENUM. 367 



(Fig. 73, 6.) This process continues along the track of 

 the needle and after seventy-two and ninety- six hours 

 the appearances shown in Fig. 73, c and d, will be pro- 

 duced. 



There is nothing particularly characteristic about its 

 growth upon agar-agar. 



On potato there appears a moist, glazed, yellowish, 

 and, at points, brownish-yellow growth that is sur- 

 rounded by a drier, colorless zone. It is not lobulated. 



In milk containing neutral litmus tincture a pink 

 color appears after two to three days at 37 C. ; after 

 four days the milk is almost decolorized and there is 

 beginning to appear coagulation of the casein with a 

 layer of clear whey above it. During the subsequent 

 twenty-four hours there is complete separation of the 

 contents of the tube into clot and whey. 



In Dunham's peptone solution it does not form indol 

 and the reaction for this body does not appear with 

 either sulphuric acid alone or plus sodium nitrite. 



It causes liquefaction of both coagulated blood-serum 

 and egg albumin. 



There is no pellicle formed as a result of its growth 

 in bouillon. 



It does not produce fermentation of glucose. 



In rosolic-acid-peptone solution its growth causes the 

 red color to become deepened after four or five days at 

 37 C. 



By Koch's method of introducing cultures into the 

 stomach of guinea-pigs this organism produced the death 

 of three out of fifteen animals experimented upon the 

 deaths resulting, most probably, more from the toxic 

 action of the products of growth that were introduced 



