1901.] Spurge (Euphorbia hiberna, L.) on Salmonoid Fishes. 53 



ingredients of the plant. The process of maceration may be repeated 

 on the same plant three or four times, and the resulting liquids will 

 still be as fatal or almost as fatal in their action on the trout as the 

 first. This, although it does not do away with the value of the 

 standard chosen, shows that the active ingredient or ingredients are 

 present in the plant in larger quantity than is represented by the 

 standard fresh extract. Further it shows that the deadliness of the 

 plant, when placed in the Irish rivers, is not a matter of a few minutes 

 only, but of many hours and even days. 



The fresh extract prepared as described has all the characteristics 

 which have been already given. In addition, however, it is highly 

 oxidisable, as its power of rapidly decolourising potassium perman- 

 ganate shows. It should be mentioned also that the composition of 

 the plant may vary throughout the year, and that the above examina- 

 tions were made in May and June. The changes which the extract 

 undergoes on exposure to air, as well as the initial composition of the 

 plant and its change during the year, demand more thorough deter- 

 mination ere a complete explanation can be given of all the effects the 

 plant-extract produces. Here it is only possible to account for a few, 

 but perhaps the most important phenomena. 



Action of the Fresh Spurge-extract and Latex. 



When rubbed on the skin, no sensation is noticeable, but the surface 

 becomes dry and rough. Later, the part becomes slightly flushed. 

 When taken by the mouth in small quantities it has a nauseous, dis- 

 agreeable taste. At the back of the tongue and in the gullet it 

 produces an irritant, burning sensation, which remains for several 

 hours. Salivation, if any, is very slight. In the stomach it has 

 little effect. At first there is a slight tendency to nausea, but this 

 soon passes away and no ill-effects of any kind ensue. 



The solution which has stood for some time and been repeatedly 

 filtered, loses this effect. It is still slightly acid, and leaves a soft, 

 soapy sensation on the back of the tongue, whilst in the stomach it 

 has no effect whatsoever. 



It is said that the salmon which are killed by the Spurge-extract in 

 the Irish rivers are used as food without any ill-effects resulting. In 

 ■order to test this point, a stray kitten which had wandered into the 

 Oatty Laboratory was permitted to feed upon the poisoned trout. 

 When no signs of poisoning were shown, the emulsion obtained 

 from the extract after removal of the volatile substance, was placed 

 in its milk — about a quarter being emulsion. This diet w T as continued 

 for 4 days, at the end of which time the kitten appeared in good 

 condition and health, and its appetite for the poisoned trout and milk 

 had in no way diminished. But not only has the Spurge-extract little 



