DENEKE'S SPIRILLUM 419 



in two or three days has formed a slimy layer of greyish -yellow colour, 



which rapidly spreads over the potato. On all the media the growth 



has a distinctly foetid odour. A growth in peptone solution fails to give 



the cholera-red reaction at the end of twenty-four hours, though later a 



faint reaction may ap - 



pear. As stated above, Koch 



succeeded in producing, 



by this organism, an intes- 



tinal affection in guinea-pigs _ 



after neutralising the stom- A ^ ^ \S* 



ach contents and paralysing r ^ w s 



the intestine with opium. Jjjjj ^^ ^ 



This occurs in a small pro- 



portion of the animals ex- t /)</* ^1) V '!/ 



perimented on, and the con- ^ ^ 



tents of the intestine, unlike 



what was found in the case 



of the cholera organism, ^ iy/~ I if 



were turbid in appearance, ^\\\/"^ 



and had a markedly foetid 



odour. When tested by in- 



traperitoneal injection, its "*Xr^-* 



effects are somewhat of the *^ ~-f j 



same nature as those of the 



cholera organism, but its 



virulence of a much lower FlG ' Hl.-Fmkler and Prior s spirillum ; from 



orc j er an agar culture of twenty - four hours 



Stained with carbol-fuchsin. x 1 000. 



from the cavity of a decayed 



tooth in a human subject is almost certainly the same organism as 



Finkler and Prior's spirillum. 



Deneke's Spirillum. This organism was obtained from old cheese, and 

 is also known as the spirillum tyrogenum. It closely resembles Koch's 

 spirillum in microscopic appearances, though it is rather thinner and 

 smaller Its growth in gelatin is also somewhat similar, but liquefaction 

 proceeds more rapidly, and the bell-shaped depression on the surface is 

 larger and shallower, whilst the growth has a more distinctly yellowish 

 tint. The colonies in plates also show points of resemblance, though the 

 youngest colonies are rather smoother and more regular on the surface, and 

 liquefaction occurs more rapidly than in the case of the cholera organism. 

 The colonies have, on naked-eye examination, a distinctly yellowish col our. 

 The organism does not give the cholera-red reaction, and on potato it 

 forms a thin yellowish layer when incubated above 30 C. When tested 

 by intraperitoneal injection and by other methods it is found to possess 

 very feeble, or almost no, pathogenic properties. Koch found that this 

 organism, when administered through the stomach in the same way as 

 the cholera organism, produced a fatal result in three cases out of 

 fifteen. Deneke's spirillum is usually regarded as a comparatively 

 harmless saprophyte. 



