4o4 MICRO-ORGANISMS IN WATER 



BACILLUS UBIQUITUS 



Authority. --Jordan, A Report on certain Sjiecies of Bacteria observed in 

 Sewage, State Board of Health, Massachusetts, 1890, ' Purification of Sewage 

 and Water,' p. 830. 



"Where Found. Isolated from the Lawrence sewage; also found in natural 

 waters and occasionally in the air. Jordan (loc. cit.) states that this bacillus 

 resembles very closely the B. candicans isolated from soil and described by 

 Percy and G. C. Frankland (loc. cit.), but differs chiefly in its power of reducing 

 nitrates, whereas the B. candicans does not. 



Microscopic Appearance. Small short plump bacilli, closely resembling 

 micrococci, I'l to 2jU long and about 1 /j. broad. Very variable in form. In broth 

 cultures it exhibits a slight tendency to form short threads. It is not motile. 



Cultures. 



GELATINE PLATES. Forms small roundish, often oval, colonies of a yellowish 

 tinge. In two days the surface colonies resemble drops of milk, being white 

 glistening projections. These centres slowly spread, become somewhat irregular, 

 and take on a dull brownish cast. Under a low power the young colonies are 

 smooth-rimmed, with a finely granular interior. No liquefaction takes place. 



GELATINE TUBES. Produces a nail-like growth, the colour being at first a 

 lustrous porcelain white, but later a dull brownish grey. 



AGAR-AGAU. Forms a good, whitish grey growth on the surface and along 

 the inoculation line. The surface growth has a slightly metallic lustre. 



POTATOES. Exhibits a white and restricted shining growth. 



MILK. The milk is coagulated in eighteen hours at 37 C., and gives a strong 

 acid reaction. 



BROTH. --Renders it turbid, forming a considerable fiocculent deposit. On 

 old cultures a thin skin forms on the surface, but this falls to the bottom on 

 slightly jarring the tube. 



Remarks. Reduces nitrates vigorously. (See p. 4:',:}.} 



BACILLUS SUPERFICIALIS 



LIQUEFIES GELATINE 



Authority. Jordan, A Report on certain Species of Bacteria observed in 

 Hi-waye, State Board of Health, Massachusetts, 1890, 'Purification of Sewage 

 and Water,' p. 833. 



Where Found. -Found frequently in Lawrence sewage. 



Microscopic Appearance. Fair-sized plump bacilli, about 2-2 /i long and 

 1 fjL broad, with rounded ends. Generally occurs singly or in pairs. No spore 

 formation observed. It is motile. 



Cultures. 



GELATINE PLATES. Under a low power the colony is nearly round, but is 

 divided by irregular lines into angular lumps, giving a somewhat cracked 

 appearance to the whole colony. The surface colonies are round, homogeneous, 

 finely granular expansions. To the naked eye the colony resembles a projecting 

 translucent drop. The gelatine is slowly liquefied, after which the colony has 

 a yellowish brown opaque centre, and a translucent edge. 



GELATINE TUBES. Grows slowly, requiring nearly ten days to liquefy the 

 gelatine to the walls of the test-tubes. Grows almost solely on the surface, only 

 the scantiest growth appearing along the inoculation line. 



AGAK-AGAR. Forms a moist, lustrous, grey translucent growth. After 

 several weeks the growth is still smooth and shiny, and has assumed a light 

 brown tint. 



POTATOES. - Refuses to grow on this medium. 



MILK. No visible change takes place, although the reaction is slightly acid. 



BROTH. Renders the liquid turbid very slowly. No pellicle is formed, but 

 a slight white precipitate is produced after some time. 



Remarks. It grows Ix-ttcr at 37 C. than at 21~ ('. Xo reduction of the nitrates 

 observed, i 



