508 MICRO-ORGANISMS IN WATER 



STEEPTOCOCCUS ALBUS 



I LIQUEFIES GELATINE I 



Authority. Maschek, Jahresbericht dcr Oberrealschulc zu Leitmeritz, 1887. 



Where Found. In water. 



Microscopic Appearance. Cocci, which are motile only during the period 

 of division. 



Cultures. 



GELATINE PLATES. Flat expansions with a white periphery. Under a low 

 power a small dark yellow cloud is visible in the centre. Liquefaction proceeds 

 rapidly. 



GELATINE TUBES. Forms a flat expansion, which rapidly liquefies the gela- 

 tine and produces a white deposit. 



POTATOES. Grows rapidly, producing a slimy expansion. 



STEEPTOCOCCUS VEEMIFOEMIS 



LIQUEFIES GELATINE | 



Authority. Maschek, Jahresbericht dcr Oberrealschulc zu Leitmeritz, 1887. 



Where Found. In water. 



Microscopic Appearance. The individual cocci are almost always so 

 arranged that they resemble filaments which have a slow vermiform movement. 



Cultures. 



GELATINE PLATES. Forms yellowish white centres, which sink into the 

 gelatine ; the centre is light, whilst the periphery is composed of a dark ring. 

 Under a low power the contents of the colony are granular, whilst the rim 

 exhibits a radiated structure. It liquefies the gelatine very rapidly. 



POTATOES. Forms a dirty yellow expansion, which grows very quickly. 



STEEPTOCOCCUS MIEABILIS 



Authority. Roscoe and Lunt, ' Contributions to the Chemical Bacteriology 

 of Sewage,' Phil. Trans. Royal Society, vol. clxxxii., 1892, p. 648. 



Where Found. In seNvage. 



Microscopic Appearance. Streptococci, forming very long chains. The 

 individual cocci are 0-4 /j. thick, but the diplococci undergoing fission are about 

 1-2 n. It is not motile. 



Cultures. 



GELATINE PLATES. It grows badly ; the depth colonies, even after four days, 

 are mere microscopic dots or gnarled and convoluted thread-like masses. Some 

 surface colonies exhibit an exceedingly faint and transparent expansion, about 

 2 millims. in diameter. Under a low power it is seen to consist of a mass of 

 fine long threads, sometimes throwing out processes into the surrounding gela- 

 tine. No liquefaction takes place, and growth apparently ceases after the first 

 five or six days. 



GELATINE TUBES. Produces an exceedingly faint and transparent film, 

 almost invisible to the naked eye. It attains a diameter of about three to five 

 millims. in a few days, after which the growth ceases. 



AGAR-AGAE. Resembles the growth on gelatine. 



POTATOES. Inappreciable growth. 



BROTH. In forty-eight hours nearly the maximum growth has taken place ; 

 a fine mass resembling delicate cotton-wool collects at the bottom of the tube, 

 or is carried upwards in delicate festooned threads by the convection currents 

 in the liquid. The threads sink, however, to the bottom when taken out of 

 the incubator (20 to 23 C.), and the broth above remains perfectly clear. 



Remarks. It grows quite as readily in broth in an atmosphere of pure hydrogen 

 as in air. Its power of absorbing atmospheric oxygen was investigated. After seven 

 days it was found to be almost nil. For an account of the methods employed con- 

 sult the original paper, p. 637. 



