UNITED STATES DEPARTMENT OF AGRICULTURE 

 BULLETIN No. 125 



Contribution from the Bureau of Plant Industry, Wm. A. Taylor, Chief, 

 and the Bureau of Animal Industry, A. D. Melvin, Chief 



Washington, D. C. 



PROFESSIONAL PAPER 



May 13, 1915 



ZYGADENUS, OR DEATH CAMAS 



By 



C. DWIGHT MARSH and A. B. CLAWSON, Physiologists 

 and HADLEIGH MARSH, Veterinary Inspector 



CONTENTS 



Page 



Introduction 1 



Description of Zygadenus 4 



Common Names of Zygadenus ... 6 



Poisonous Species of Zygadenus . . 6 



Losses of Live Stock by Zygadenus . . 6 



Animals Poisoned by Zygadenus ... 7 

 Symptoms Produced by Zygadenus 



Poisoning 7 



General Statement of Experimental 



Work 8 



Symptoms in Sheep Observed at the 



Greycliff Station 24 



Symptoms in Horses and Cattle . . 29 



Autopsies 29 



Page 

 Toxic and Lethal Dose of Zygadenus 



Venenosus for Sheep 30 



Experiments with Horses and Cattle . 34 

 Comparative Toxicity of Different 



Species of Zygadenus 35 



Does Toxicity Vary with Locality . . 35 

 Effect of Repeated Feeding in Produc- 

 ing Immunity or Increased Suscepti- 

 bility 37 



Remedies ,, . . . 37 



Methods of Preventing Losses ... 43 



General Summary 44 



Literature Cited 45 



WASHINGTON 

 GOVERNMENT PRINTING OFFICE 



1915 



