258 BACTERIOLOGY 



tures show a superficial deposit possessing concentric rings, 

 which may be described as diurnal rings, since a difference 

 exists between the growth in the dark and that in dayhght, 

 which expresses itself in this form (fig. 92). If the 

 culture he kept in the dark the con- 

 centric circles on the upper surface 

 disappear. On agar there appears a 

 deposit showing scroll-like tracings, 

 and on potato growth takes place 



MicKoc^co^ns"^" ^T^of^nf ^^ ^^^ ^^^^ 0^ inoculation (fig. 93.) 

 coscESTEicns. rpjjg microbe cannot be found to 



possess any pathogenic properties, subcutaneous inocula- 

 tions upon mice having produced no results. 



The Urine. 



Micro-organisms of the urine. — In the normal state no 

 micro-organisms .are found in urine when freshly passed ; 

 those which appear in it reach it from without, or are de- 

 rived from diseased conditions of the urinary passages. If, 

 however, the urine stands for some time until alkaline fer- 

 mentation sets in, a multitude of yeasts, moulds, cocci, 

 and bacilli make their appearance, which, reaching the urine 

 probably from the air, and finding there a favourable environ- 

 ment, set up a fermentation of the urinary sugar and cause 

 a splitting up of the urea into ammonium carbonate ; in 

 fact, an entire series of processes taking place in the urine 

 are dependent on the vital activity of micro-organisms. 



A true bacterinria has also been described in different 

 quarters (Eoberts, Schottelius, Fischer), which appears to 

 be of a morbid nature : in pathological processes in the 

 different organs, but especially when bacteria get into the 

 blood and therewith also into the renal circulation, bacilli 

 may penetrate mto the urine during its secretion and be 

 expelled with it. 



