440 APPENDIX 



These come to the surface, spread out as thin yellowish opalescent growths, 

 which do not liquefy the gelatine. Under the microscope small charac- 

 teristic deep growths, with a dark brown colour and having somewhat the 

 concentric appearance of the Spirillum concentricum, are seen. The super- 

 ficial growths are usually paler in colour, and are slightly yellow in the 

 centre. The margins are toothed, and the whole surface has somewhat the 

 appearance of a network. 



In tube cultures it grows almost like the typhoid bacillus. Yellowish- 

 white points make their appearance along the line of the needle, whilst on 

 the surface there is a greyish-white glistening layer with scalloped margins. 

 The surrounding gelatine becomes somewhat cloudy, but there is no lique- 

 faction. On agar-agar it grows as a white moist layer, which has no special 

 characteristics. On potatoes it forms a yellowish- brown viscid layer which 

 has a somewhat characteristic appearance. 



It occurs as short rods with rounded ends, which usually remain single, 

 but are sometimes united into long threads. It forms spores, and can grow 

 anserobically. 



t It is said that it is also found in the faeces of healthy individuals, in the 

 air, and in putrefying fluids, and that it is not necessarily found in cases of 

 cholera. It is certainly not found in all cases of cholera, and it is now 

 thought that it may be nothing more than the ordinary faeces bacterium. 



(2) The Spirillum rubrum was first obtained by Von Esmarch from the 

 body of a mouse. It grows extremely slowly, and cannot be made out in plate 

 cultivations for about five days. Under the microscope the points, which 

 are exceedingly small, have a yellowish -red appearance, are finely granular, 

 and have sharp margins. In the presence of oxygen no colouring matter is 

 formed, but in the deeper part of the needle track in a puncture culture 

 there is a beautiful wine colour developed, the surface growth having a 

 moist appearance and well-defined margins. It is a somewhat thick, 

 transparent, homogeneous, screw-like spirillum with three or four to 

 forty spirals ; is extremely motile, and is provided with flagella. Its vege- 

 tative multiplication is by transverse division. It probably forms spores, 

 as it is resistant to the action of drying, although it cannot withstand 

 a temperature of more than 50 C. It multiplies at a temperature of between 

 16 and 40 C., but most actively at the temperature of the body. In solid 

 cultures the rods are short, but in fluid media the spirals are well developed. 

 It is non-pathogenic. 



(3) Spirillum concentricum occurs in putrefactive blood ; it was first 

 described by Kitasato, and probably belongs to the same group as the 

 larger spiral bacteria that are frequently found in that substance. It grows 

 rapidly at the temperature of the room on plate cultivations, forming 

 greyish-white, round, smooth, well-defined colonies, each of which appears 

 to grow with concentric marking, and looks almost like a cockade; hence 

 the name. In gelatine it gives rise to no liquefaction, and grows better on 

 the surface than deeper down along the needle track. It does not grow on 

 potatoes, and is apparently non-pathogenic. 



Like the Spirillum rubrum, it forms short spirals on nutrient media, but 

 long spiral threads on fluid media. It is motile, and is provided with 

 flagella. 



III. The organisms have not yet been cultivated on artifi- 

 cial media. 



