BY JAMES M. PETKIE. 



631 



been brought by Mr. Maiden from Aberdeen in 1907, from a spot 

 on which cattle had died in November of that year. The cause of 

 the fatality was associated with this grass. Samples were also 

 obtained, through the Chief Inspector of Stock, from Scone and 

 Muswellbrook, and these all gave strong positive reaction at this 

 same season. A second fatality took place at Forbes, where over 

 100 sheep died on December 9th, 1911. This grass was recognised 

 on the spot, and when tested gave a very strong reaction. A third 

 fatality occurred in the same district in February, 1913; after 

 which some sheep were isolated and fed on this grass alone, when 

 each of them died within half an hour. A sample of this same lot 

 was received for analysis, from the Inspector of Stock at Forbes, 

 and gave the following result : — 



In fresh material. 



Free hydrocyanic acid 



Combined hydrocyanic acid 



Total hydrocyanic acid 



In grass dried at 

 100°C. 



0-008 % 

 0-017 % 



025 % 



The free acid was estimated by destroying the enzyme with boil- 

 ing water, and distilling into standard alkali. The distillate was 

 then titrated with silver nitrate. 



The total acid was estimated by previous fermentation of the 

 grass, and then distilling off the volatile acid. 



It was calculated from the free acid figure that a sheep of 150 

 lbs. weight would require, for a lethal dose, to eat about 2 lbs. 

 weight of this grass. 



Effect of drying on cut grass. — Grass which gave a very strong 

 reaction for hydrocyanic acid, when exposed openly to the air, 

 showed a gradual diminution of the intensity of reaction during 

 three weeks. At the end of this time the grass reacted only very 

 faintly, and usually in the fourth week gave negative tests. When 

 now, this grass was moistened, and emulsin added, it still gave 

 negative results, but on adding amygdalin instead, a strong positive 



