INTRODUCTION 23 



example, the aconite and cherry laurel. The rule is not 

 absolute ; thus rhododendron, veratrum, and the hellebores 

 are flourishing and dangerous in Alpine districts. A scrutiny 

 of the distribution of poisonous plants in Great Britain, 

 however, soon satisfies one that they are less numerous 

 in Scotland than in England, and in the latter country 

 more often found in the south than in the north. 

 Poisonous plants are particularly common in rocky and 

 arid districts, especially near the sea. One is struck by 

 the profusion of Solanwm dulcamara and nigrum, of hyo- 

 scyamus, and of the horned or sea poppy in the more sandy 

 coast localities of the South of England. 



As regards warmer latitudes, poisonous plants are both 

 more numerous and usually more virulent. 



As to cultivation, this is well known to lead to a diminu- 

 tion in the generation of poison by a plant. Since the 

 presence of poison is no doubt a measure of natural protec- 

 tion, one understands how this occurs ; for Nature never 

 wastes energy, and when the preservation of a species is 

 assured, there is no need to elaborate poison. An excellent 

 instance is the Phaseolus, or French bean, which is harm- 

 less, whilst the uncultivated variety, Phaseolus hmatus, con- 

 tains a cyanogenetic glucoside. Aconite is another species 

 whose poisonous properties diminish on cultivation. 



The hemlocks are often eaten by cattle, and both cattle 

 and horses frequently crop overhanging growths of yew, 

 rhododendron, aconitum, and other plants. The throwing 

 of garden clippings over the fence is a common cause of 

 disaster. Those responsible ought to remember that 

 common garden shrubs and flowering plants comprise 

 many poisonous species, and it would be a safe rule to 

 regard all as dangerous. 



KINDS OF POISONING. 



The course of poisoning follows three types — acute, sub- 

 acute, and chronic — dependent on the dosage. 



Acute poisoning manifests the intense symptoms, and 



