MICROSCOPICAL AND CULTURAL CHARACTERS 439 



pairs, sometimes in short threads. Under certain conditions 

 it forms spores which are oval in shape, usually terminal in 

 position, and only a little thicker than the bacilli. It is a motile 

 organism, and has 4 to 8 lateral flagella of wavy form. It stains 

 readily with the ordinary dyes, and also retains the colour in 

 Gram's method, though care must be employed in decolorising. 



The organisms can be readily cultivated on the ordinary 

 media, but only under strictly anaerobic conditions. In glucose 

 gelatin a whitish line of growth forms with lateral offshoots, 

 but liquefaction with abundant gas formation soon occurs. In 

 gelatin plates the colonies after four to six days are somewhat 

 characteristic; they appear to the naked eye as small semi- 

 transparent spheres, and these on examination under a low 

 power of the microscope have a yellowish-brown colour and are 

 seen to be composed of granules which show a streaming move- 

 ment, especially at the periphery. Cultures in glucose agar 

 resemble those of certain other anaerobes ; there is abundant 

 development of gas, and the medium is split up in various 

 directions. The cultures have a rancid, though not foul, odour, 

 due chiefly to the development of butyric acid. It does not 

 liquefy coagulated serum and M'Intosh places it in the non- 

 proteolytic group. He finds that it ferments glucose, with 

 evolution of gas, and, to a less extent, maltose, lactose, glycerine, 

 and starch. The optimum temperature is below that of the body, 

 namely, between 20° and 30° C. ; at the body temperature growth 

 is slower and less abundant and spore formation does not occur. 



Pathogenic Effects. — Like the tetanus bacillus, the bacillus 

 botulinus has little power of flourishing in the tissues, whereas it 

 produces a very powerful toxin. Van Ermengem found that the 

 characteristic symptoms could be produced in certain animals 

 by administering watery extracts of the infected ham or cultures 

 either by the alimentary canal or by subcutaneous injection. 

 Here also there is a period of incubation of not less than six to 

 twelve hours before the symptoms appear, and when the dose is 

 small a somewhat chronic condition may result, in which local 

 paralyses form a striking feature. The characteristic effects can 

 also be produced by means of the filtered toxin by either of 

 the methods mentioned, though in the case of administration by 

 the alimentary canal the dose requires to be larger. As in 

 the case of the tetanus poison, the potency of the toxin is 

 remarkable, the fatal dose for a guinea-pig of 250 grm. weight 

 being in some instances '0005 c.c. of the filtered toxin. In cases 

 of poisoning in the human subject, the effects would accordingly 

 appear to be produced by absorption of the toxin from the 



