52 



Dr. H. M. Kyle. On the Action of the [June 25, 



In E. lathyris as well as in other species of the Euphorbiacese, malic 

 acid in the form of its calcium and other salts occurs in abundance, 

 and it is possibly present in E. hiberna. If present in the acid form in 

 the extract, it would account for some of the changes that occur when 

 the extract is exposed to air, but otherwise it is of little importance. 



In his description of E. resinifera, Fliickiger mentions the presence 

 of a compound which he calls Euphorbon, with the composition 

 C15H24O or C2oH 3 , 5 0. Whether this substance, probably an oxidation 

 product, or any similar substance, is present in E. hiberna was not 

 determined, and it is due in part to the incompleteness of the chemical 

 analysis of the plant, that certain discrepancies to be shown hereafter 

 can not be fully explained. 



It is necessary to mention the various extracts of the Spurge that 

 were employed, and the methods by which they were prepared. What 

 will be referred to as the " fresh extract " means an aqueous extract 

 which has been prepared by washing and chopping up the stems, roots, 

 and leaves of the plant, and allowing them to stand in water within a 

 closed vessel. The vessel was shaken well several times, and at the 

 end of 2 hours the liquid was poured oft', filtered once, and measured. 

 The aim of this method was to obtain an extract resembling as nearly 

 as possible that which is employed in Ireland in poisoning the rivers, 

 and was decided upon after various trials. It was found that if more 

 than 2 hours were given to the formation of the extract the emulsion 

 tended to break up and disappear. If the chopped-up plant was left 

 for 24 hours in water the emulsion still persisted, but was not so thick 

 and disappeared on once filtering, whereas on standing for 2 hours only, 

 the emulsion passed through the filter and remained in the filtrate. 

 The reason for filtering at all was to get rid of a large amount of 

 woody and insoluble material which could play little or no part in the 

 action of the Spurge on fishes, but made the liquid turbid and obscure. 



Whether the emulsion was present or absent, and whether the 

 liquid was poured off from the plant at the end of \ hour or 4 days, 

 made no difference in the fatal effects which it had upon the trout. 

 But it was found desirable to have some standard solution with which 

 all other extracts and preparations could be compared. The standard 

 was arrived at by comparing the amount of the liquid drawn off with 

 the weight of the plant employed — 1 c.c. of liquid to 1 gramme of plant 

 being taken as the 100 per cent, extract. When percentages of the 

 fresh extract are spoken of, therefore, they are calculated from this as 

 the standard. 



This is admittedly a rough measure and for two reasons. On the 

 one hand, it does not express the percentages in terms of the active 

 ingredient, which would have been very desirable indeed had it been 

 possible. On the other hand, the short space of 2 hours during which 

 the plant is macerated, does not by any means exhaust the active 



