APPENDIX. 439 



liquefied. This organism grows on potatoes at the ordinary temperature of 

 the room as a yellowish white layer. Organisms slightly larger than 

 Koch's bacillus, frequently somewhat pointed at the ends. The spirals are 

 as a rule not so long and not so perfect as the cholera bacillus, involution 

 forms being more frequently met with. The odour is Very disagreeable. The 

 organism is more resistant than the cholera bacillus ; it is not nearly so 

 fatal to guinea-pigs, though a certain number usually succumb to its action. 

 It was supposed to be obtained from cases of cholera nostras, but it is 

 probable that it is merely one of those spirilla which are met with in the 

 alimentary canal under ordinary conditions, similar to those described as 

 organisms of the mouth. 



(3) Deneke's cheese bacillus (Spirillum tyrogenum). — Plate colonies 

 under microscope similar to those of the Finkler and Prior bacillus, 

 but brownish in colour. It grows very rapidly as plate cultivations, 

 and gives rise to liquefaction of the gelaline, not so rapidly as the Tinkler 

 and Prior bacillus, but more rapidly than the cholera bacillus. It 

 also forms a yellowish -white layer on agar-agar and blood serum. It 

 was first described as giving rise to no growth on potato at any tempera- 

 ture, but is now found to grow as a yellow layer on this medium. 

 This bacillus is somewhat smaller than the cholera bacillus. Forms long 

 spiral threads, in which the spirals are close and very perfect ; like the 

 previous bacillus, it is exceedingly motile. When introduced into the 

 duodenum of the guinea-pig, according to Koch's method (p. 164), kills 

 about twenty per cent, of the animals, but the organism under ordinary 

 conditions is probably non-pathogenic. 



(4) The Vibrio Metscknikoff was first observed by Gamaleia in the con- 

 tents of the intestine of a fowl. Its growth on gelatine plates resembles 

 that of the Finkler-Prior bacillus ; although it does not liquefy gelatine 

 quite so rapidly, it gives rise to the same peculiar cloudiness. It 

 sometimes resembles the Finkler-Prior, at others the Koch comma bacillus, 

 and sometimes the cheese bacillus cultures. It grows in gelatine, on 

 agar, and on potatoes, as does the cholera bacillus, but in bouillon it 

 causes turbidity of the fluid at an early date, and a thin film soon appears on 

 the surface. It gives the cholera red reaction on the addition of sulphuric 

 or hydrochloric acid, just as does the cholera bacillus. It is an organism 

 very like the cholera bacillus in many respects, and is certainly closely 

 related to it. It occurs as a somewhat curved bacterium, shorter and 

 thicker, but rather more bent, than Koch's comma bacillus. In fluid 

 media it forms regular spirals. It is provided with long delicate wavy 

 flagella, and is motile. Metschnikoff has described it as being capable of 

 passing through a whole series of changes in form, and as being one of the 

 best examples of polymorphism. Apparently it does not form spores. It 

 is pathogenic ii! the case of hens, guinea-pigs, and pigeons, but does not 

 affect mice. 



II. The gelatine is not liquefied. 



(i) Emmerich's bacillus is a special form of bacillus which was de- 

 scribed in the cholera epidemic of Naples (1884). It occurred along with 

 the true cholera organism, and was obtained in the alimentary canal and 

 was said by Emmerich to occur in the blood of patients who had died 

 from cholera. 



On plate cultivations colonies grow deep down as small white points. 



