MICROSCOPICAL AND CULTURAL CHARACTERS 395 



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. The optimum 

 temperature is below that of the body, viz., 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. Here also, 

 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 

 alimentary canal ; it is only after or immediately before death 

 that a few bacilli may enter the tissues. Van Ermengem 

 obtained a few colonies from the spleen of a patient who had 

 died from ham-poisoning. The properties of the botulinus toxin 

 have been investigated and have been found to correspond 

 closely, as regards relative instability, conditions of precipitation, 

 etc., with the toxins of diphtheria and tetanus. An antitoxin 

 has also been prepared by Kempner by the usual methods, and 

 has been shown not only to have the neutralising property but 

 to have considerable therapeutical value when administered 

 some hours after the toxin. The direct combining affinity of 

 the toxin for the central nervous has been demonstrated by 

 Kempner and Schepilewsky by the same methods as Wassermann 

 and Takaki employed in the case of the tetanus toxin. The 



