412 MICRO-ORGANISMS IN WATER 



BACTERIUM THOLOEIDEUM 



Authority. Gessner, Arcliiv fttr Hygiene, vol. ix. p. 129. 



Where Found. In the intestinal tract of healthy people. In water suspected 

 of causing typhoid fever by Schardinger, Wien. klin. Wocliensclirift V., Nos. 28, 

 29. (Centralblatt f. Bakteriologie, vol. xv. p. 48.) 



Microscopic Appearance. Short rods with rounded ends, also in oval forms. 

 Eesembles B. lactis aerogenes (see below), also in its mode of growth. 



Cultures. 



GELATINE PLATES. On the surface the colonies form at first nail-head 

 growths of slimy, stringy consistency, and of an opaque, dirty white colour ; 

 later they lose their slimy character, and form large circular expansions, with 

 a grey centre surrounded by concentric grey rings. Under a low power they 

 are circular and smooth-rimmed, with a colourless, bright and shining periphery. 

 From the centre brownish yellow very fine radial lines extend, but they become 

 yellow as they approach the periphery. Later the centre becomes greyish 

 brown and the remainder grey, whilst the bright peripheral zone disappears. The 

 depth colonies are whetstone-shaped and are of a yellowish white colour. 

 Under a low power they are at first olive green in colour, later dark grey -green, 

 and then resemble date stones in shape. 



GELATINE TUBES. Forms a moist, shining convex expansion, which later 

 becomes thick and spreads over the whole surface. In the depth it forms a 

 yellowish white thick band with closely packed small round extensions, having 

 button-shaped and thick ends. 



AGAR-AGAR. Forms a moist thick expansion. 



POTATOES. In from two to three days forms a shining, yellowish expansion, 

 which rapidly spreads over the whole surface and has a slightly lobular and 

 sharply defined edge. On one occasion small bubbles of gas were found on a 

 potato culture four days old. 



Remarks. Grows at the ordinary temperature. It is pathogenic to mice (thus 

 distinguished from the B. lactis aerogenes) and guinea-pigs. The bacteria are found 

 in the blood and organs of the body, and are easily isolated and cultivated. 



BACTERIUM LACTIS AEROGENES 



Authority. Escherich, ' Die Darmbakterien des Sauglings u. ihre Bezie- 

 hung z. Physiol. d. Verd.,' 1886, Fortschr. dcr Medicin, 1885, No, 15. 



Where Found. In the intestinal tract of animals and people fed with milk, 

 especially in that of suckling children and animals. Found also once in un- 

 boiled cow's milk. Found in urine in cases of pneurnaturia, by Heyse (Centralbl. 

 f. Bakt., vol. xv., 1894, p. 322). Found by Schardinger (loc. cit,) in water 

 suspected of causing typhoid fever. 



Microscopic Appearance. Short plump rods 0*5 to 0'8 M broad and 1 to 2 M 

 long, with rounded ends. Usually arranged in pairs side by side ; also found 

 grouped together in irregular heaps. It is not motile. No spore formation 

 observed. 



Cultures. 



GELATINE PLATES. Forms on the surface convex isodiametric moist 

 shining porcelain-white colonies ; in the depth yellowish round centres. No 

 liquefaction ensues. 



GELATINE TUBES. Grows abundantly along the needle's path in the depth, 

 and produces a nail-head shaped expansion on the surface. 



POTATOES. Produces vigorous white centres impregnated with bubbles of 

 gas. The colonies sometimes run together and resemble cream. 



BLOOD SERUM. Forms a raised, moist, shining, white expansion. 



Remarks. When subcutaneously introduced into rabbits and guinea-pigs, these 

 animals, especially the latter, die in from one to three days, and the bacilli are found in 

 the blood and organs. It is not pathogenic to mice. It grows best at the temperature of 

 the body. It is aerobic, and facultatively anaerobic in milk, sugar, and grape sugar 

 solutions ; in these media when thus grown it produces gas consisting of carbonic 

 anhydride and hydrogen. 



