56 Bulletin No. 207. 



phonia, enuresis, obstinate constipation, decumbency, con- 

 sciousness or semi-consciousness. Barely do affected animals in 

 our observations show a rise in body temperature at any stage 

 of the disease. More often the body temperature is subnormal. 

 The gross anatomic alterations in horses and mules arti- 

 ficially infected with B. botulinus are quite similar to the le- 

 sions observed in animals naturally affected with forage poison- 

 ii?g. In animals peracutely affected but slight gross pathologic 

 change is found, yet in experimental horses infected with B. 

 botulinus the course of the infection may exhibit premonitory 

 symptoms extending over a few days. In subacute botulism 

 in horses gross anatomic alterations at death are variable 

 but may involve changes in the mucous and serous membranes, 

 the meninges, lungs, heart and kidneys. The toxic lesions are 

 quite indistinguishable from the changes observe^ in horses 

 and mules naturally afflicted with forage poisoning. 



Pathogenesis of B. botulinus. 



To observe the effect of B. botulinus upon animals, active" 

 cultures of the organism were obtained from Dr. Buckley*, 

 Acting Chief of the Pathological Division of the Bureau of 

 Animal Industry, from Dr. Kligler, of the American Museum 

 of Natural History, and from Dr. Jordan, of the University of 

 Chicago. 



Horses, Mules and a Jennet: Experimental horses fed 2 

 to 7 cc. of broth culture of this organism in wholesome feed 

 invariably succumbed in 3 to 10 days. 0.1 cc. of the unfiltered 

 broth culture injected subcutaneously proved fatal. A jennet 

 receiving per os the entire growth of one agar slant succumbed. 

 Repeated large amounts of the unfiltered broth culture fed to 

 chickens produced no noticeable effect, but the naturally 

 voided feces from these fowls when disguised in wholesome 

 feed and given to a mule produced characteristic manifestations 

 and death. 



The clinical symptoms observed in horses, mules and a 

 jennet varied in intensity. The peracute cases were frequently 



"The strain of B. botulinus used in the following experiments was ob- 

 tained from Buckley and designated N. B. S, strain.. 



