BACTERIA, NOT CLASSIFIED. 723 



is added an abundant development occurs, and numerous very minute crys- 

 tals are scattered through the culture medium. In urine alkaline fermenta- 

 tion is quickly induced, and an abundant deposit of crystals of ammonio- 

 magnesian. phosphate and of alkaline urates, together with the bacilli, 

 accumulates at the bottom of the test tube ; this deposit acquires a blackish 

 color. The most favorable temperature for the growth of this bacillus is 30 

 to 40 C. 



464. UROBACILLUS DUCLAUXI (Miquel). 



Obtained by Miquel (1879) in the water of sewers, and subsequently in 

 river water very common and widely distributed. 



Morphology. Slender filaments, from 0.6 to 0.8 in diameter and from 

 2 to 10 u long. In alkaline bouillon it may attain a diameter of 1 ft ; the ba- 

 cilli are frequently united in chains. 



Biological Characters. An aerobic and facultative anaerobic, motile, 

 liquefying bacillus. The movements are comparatively slow. Forms 

 spores located at the centre of the rods, which then are spindle-shaped. De- 

 velops most rapidly at 40 C. No development occurs at 5 C., but at 8 to 

 10 the fermentation of a culture medium containing urea is accomplished in 

 about a month, and at 20 in two or three days. Does not grow in ordinary 

 bouillon or nutrient gelatin, but grows in the usual culture media when they 

 are rendered alkaline by the addition of ammonia, or when urea is added. 

 In nutrient gelatin containing urea numerous small, white colonies are de- 

 veloped along the track of the needle, and a quantity of minute crystals are 

 scattered through the culture medium. At the end of three or four months 

 the gelatin medium is transformed into a transparent, ammoniacal, syrupy 

 liquid. In alkaline gelatin not containing urea liquefaction does not occur. 

 In bouillon made alkaline by the addition of ammonia, growth occurs, caus- 

 ing the liquid to become clouded within twenty -four hours ; later an abun- 

 dant sediment accumulates at the bottom of the tube, the liquid becomes vis- 

 cid and gives off a disagreeable odor. 



465. UROBACILLUS FREUDEXREICHI (Miquel). 



Obtained by Miquel from the air, from dust, from sewer water, etc. 



Morphology. Closely resembles Urobacillus Pasteuri, but forms longer 

 chains and has more active movements. The rods are from 1 to 1.3 n thick 

 and have rounded extremities ; the length varies considerably, but in recent 

 cultures is usually 5 to 6 ju. Under favorable conditions of temperature, 

 30 C. , actively motile filaments, consisting of six to ten elements, are de- 

 veloped in alkaline bouillon ; upon solid media long filaments, composed 

 of comparatively short elements and quite motionless, are developed. 



Biological Characters. An aerobic, liquefying, motile bacillus. Forms 

 spores. The most favorable temperature for the development of this bacillus 

 is from 33 to 35 J C. As a ferment of urea it is ten times less active than 

 Urobacillus Pasteuri. In nutrient gelatin, at 20 C , development occurs 

 upon the surface as a milk-white growth, which is visible at the end of two 

 days, and later forms a layer with irregular outlines having a diameter of 

 three to four millimetres ; but little development occurs along the track of 

 the inoculating needle ; liquefaction commences at the surface at the end 

 of eight to ten days and progresses slowly ; at the end of thirty to forty 

 days the gelatin is completely liquefied, it is of a pale-yellow color and quite 

 viscid ; an abundant white deposit accumulates at the bottom of the tube. 

 Upon gelatin plates (containing urea) small, spherical, white colonies are 

 developed in two or three days ; these gradually increase in dimensions 

 and are surrounded by an aureole of minute crystals ; later the development 

 ceases and the bacilli are killed by an excess of carbonate of ammonia re- 

 sulting from the decomposition of the urea. In neutral bouillon, at the end 

 of two or three days, a slight cloudiness is developed, and later a scanty 

 white deposit is seen at the bottom of the tube. 



