CULTURAL CHARACTERS. , 351 



Most observers have found no trace of motility, while others say 

 that it is slightly motile. Vedder and Duval have, however, by 

 modification of Van Ermengem's process, demonstrated the pres- 

 ence of numerous lateral flagella, which are of great fineness, 

 but of considerable length. No spore formation occurs; the 

 organism is stained readily by the ordinary dyes, but is decolor- 

 ised by Gram's method. 



Cultural Characters. — In these also considerable resemblance 

 is presented to the typhoid bacillus. In gelatin a whitish line of 

 growth occurs along the puncture, but the superficial film-like 

 growth is usually absent, or at least poorly marked. In plate-cul- 

 tures also the superficial growths are smaller, and have less of the 

 film-like character than those of the typhoid organism. On agar 

 growth occurs as a smooth film with regular margins, but after 

 two or three days, especially if the surface be moist, there oc- 

 curs, as Vedder and Duval have described, an outgrowth of 

 lateral offshoots on the surface of the medium. In agar plates 

 the colonies resemble those of the typhoid organism, being of 

 smaller size and less opaque than those of the bacillus coli. 

 In peptone bouillon a uniform haziness is produced and the 

 indol reaction is not usually given. This organism does not 

 ferment grape and other sugars, there being no evolution of gas 

 by ordinary methods. In litmtis milk there is developed at first 

 a slight degree of acidity, which is followed by a phase of in- 

 creased alkalinity ; no coagulation of the milk occurs. Onpotato 

 the organism forms a transparent or whitish layer, which, how- 

 ever, in the course of a few days assumes a brownish-red or 

 dirty-gray colour, with some discoloration of the potato at the 

 margin of the growth. 



Powers of Resistance. — The bacillus is killed by ten minutes' 

 exposure to moist heat at SS° C. Shiga gives the following data 

 regarding the action of some chemical solutions upon this organ- 

 ism : a 5 per cent solution of carbolic acid destroys it in a few 

 minutes, whereas a i per cent solution requires half an hour ; a 

 brief exposure to a 2o"iFo solution of bichloride of mercury suf- 

 fices to kill it ; five minutes' exposure in a lo per cent solution of 

 95 per cent alcohol causes its destruction. Exposure to direct 

 sunlight for thirty minutes kills the bacillus. Drying is resisted 

 for several days. 



Relations to the Disease. — This organism has been found in 



