82 ESSENTIALS OF BACTERIOLOGY. 



Crenothrix Kiihniana. (Rabenhorst.) Long filaments joined 

 at one end ; little rod-like bodies form in the filaments ; and 

 these break up into spores. 



ZoogUea are also formed by means of spores ; and these can 

 become so thick as to plug up pipes and carriers of water. 

 They are not injurious to health. 



Cladothrix Dichotoma. (Cohn.) Very common in dirty 

 waters. The filaments branch out at acute angles, otherwise 

 resembling the crenothrix ; accumulations of ochre-colored 

 slime, consisting of filaments of this organism, are found in 

 springs and streams. 



Beggiatoa Alba. (Vancher.) The most common of this 

 species. The distinction between this and the preceding species 

 lies in the presence of sulphur granules contained in the struc- 

 ture, and hence they are often found where sulphur or sulphides 

 exist ; but where the remains of organic life are decomposing 

 they can also be found. 



Several large spirilla and vibrio live in bog and rain-water, 

 but our space does not suffice to describe them. 



Bacterium Ureee. 



Origin. Decomposed ammoniacal urine. 



Form. Thick, little rods, with round ends one-half as thick 

 as they are long. 



Properties. Does not dissolve gelatine ; changes urea into 

 carbonate of ammonia. 



Growth. At ordinary temperatures, very slowly. In two days 

 on gelatine very minute points, which in ten days have the size 

 of a cent. The colonies grow in concentric layers. 



Micrococcus Ureae. (Pasteur and Van Tieghain.) 



Orirjin. Decomposed urine and in the air. 



Form. Cocci, diplococci, and steptococci. 



Properties. Decomposes urea into carbonate of ammonia ; 

 does not liquefy gelatine. 



Growth. Grows rapidly, needing oxygen ; can remain sta- 

 tionary below C. ; growing again, when a higher temperature 

 is reached. 



Colonies on Plate. On the surface like a drop of wax. 



