to kill. Any portion of these root stocks, when separated from the 

 parent plant, even if only an inch or so in length, is capable of pro- 

 ducing new plants. The root stocks are succulent and lose their 

 moisture very slowly so that it is difficult to kill them even by 

 exposure to drought. 



Johnson grass may serve as forage for cattle and sheep, but under 

 certain conditions, which as yet are not well understood, it may be- 

 come poisonous. For many years there have been occasional reports 

 of Johnson-grass poisoning in California. This season (1917) stock 

 losses from this cause have been numerous and several samples sub- 

 mitted for analysis have been found to contain hydrocyanic acid. 



Symptoms and Diagnosis. Hydrocyanic acid has the most rapidly 

 fatal action of any known poison. There are several vegetable alka- 

 loids which are more poisonous in proportion to their volume and 

 weight, but their lethal action is more prolonged. Instantaneous 

 death results from a very small amount of the free acid placed on 

 the tongue. In dilute form or when contained in sorghum small 

 quantities will cause severe symptoms in a few seconds. The animal 

 staggers or falls, the eyes are motionless, the heart action is slowed, 

 and the respirations are slow and convulsive. All animals are sensi- 

 tive to prussic acid, but sorghum poisoning occurs chiefly in cattle 

 and sheep. Glover and Bobbins of the Colorado Experiment Station 

 report that a cow died in ten minutes after eating a few mouthfuls 

 of poisonous kafir corn. It is said that if an animal lives thirty 

 minutes after the first symptoms develop it stands a good chance of 

 recovery. 



In non-fatal cases the symptoms observed have varied from slight 

 signs of vertigo and cessation of rumination to severe convulsions. 

 In cattle and sheep bloating may occur as a secondary effect. Re- 

 covery is rapid and most animals that recover appear normal the 

 following day, but in some instances cattle show weakness and a 

 staggering gait for several days. 



Autopsy of cattle or sheep that have died from poisoning by 

 Johnson grass or other sorghums seldom shows anything character- 

 istic. The diagnosis must be based on the history of the case and 

 the demonstration by chemical analysis of the presence of prussic 

 acid in the forage. 



Specimens for Laboratory Analysis. The analysis of the stomach 

 contents or tissues is not practicable because of the rapid disappear- 

 ance* of the poison. On the other hand, a chemical analysis of the 

 suspected sorghum is often the only way to arrive at a positive diag- 

 nosis. If animals have died and the sorghum forage is suspected, a 

 chemical examination to determine the edibility of the remaining crop 



