34 JOURNAL OP THE TRINIDAD 



division according to the length of the rods was found to be 

 impossible, for a rod at one stage of its growth or under certain 

 conditions might be a bacterium, while at another time it might 

 be long enough to be considered a bacillus. 



There are many species of bacterium associated with disease, 

 but not one has been absolutely proved to be pathogenic in man. 

 The bacterium of pneumonia discovered by Friedlander has been 

 considered by some to be the cause of pneumonia, but inoculations 

 of animals with cultivations of the bacteria have only succeeded 

 in some cases. 



In animals many pathogenic bacteria have been described, 

 such as the bacterium of diphtheria of pigeons, the bacterium of 

 fowl-cholera, the bacterium of septicaemia in rabbits, and the 

 panhistophytum ovatum which has been proved to be the cause 

 of pebrine in silk worms. 



Other bacteria are chromogenic, producing yellow, red, 

 brown, violet and other colours. The best known of these is 

 bacterium prodigiosum which occurs on bread, boiled rice, and 

 Starch paste, and has been known as the bleeding host. 



In this genus also occur the zymogenic saprophyte which 

 gives rise to the ammoniacal fermentation of urine, and also that 

 which oxidises alcohol in wine and other fruit-juices into vinegar. 



2. Spirillum. This genus contains threads which are in the 

 form of screws, and are made up of long or short rods only, or of 

 rods and cocci. Spore formation is absent or unknown. 



One of the best known examples is the spirillum of relapsing 

 fever which was described in 1873 by Obermeier. It occurs in 

 the blood of patients suffering from relapsing fever. The spirilla 

 are absent from the blood during the non-febrile intervals. 

 Carter in Bombay inoculated monkeys successfully from the 

 human subject. 



Another member of this genus which has attracted much 

 attention of late years is the comma bacillus which Koch claims 

 as the cause of cholera. His opponents, however, say that comma 

 bacilli are not found in all cases of cholera. There are also 

 possible sources of error in the inoculations of animals which 

 have baen carried out. 



Since writing the above I sae in the Lancet of February 10, 

 1SD4, that Prof. Cunningham of Calcutta has had certain distinct 

 forms of comma bacilli obtained from case3 of cholera, in con- 

 tinuous cultivation for nearly four years, all being under precisely 

 th3 same conditions of environment. These bacilli have continued 

 to present well marked differences, and Prof. Cunningham regards 

 them as distinct species. If this is so, cholera cannot be regarded 

 as due to the presence of any particular species of comma bacillus 

 in tiie intestine, 



