48 



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



distorted by the tidal influence of the satellite. The linear diameters 

 of primary and satellite are in a ratio of about 4:1. 



The points of bifurcation on the Poincare series are not investigated. 

 Since the Jacobian ellipse determined by equation (iv) is known to be 

 stable, there is ground for supposing that the series remains stable up 

 to the point of separation. It therefore appears probable that the 

 primary moves through a cycle of configurations in which Jacobi's and 

 Poincare's figures alternate. The angular momentum is decreased by 

 about 30 per cent., at the ejection of each satellite. 



" On the Action of the Spurge (Euphorbia hiberna, L.) on Salmonoid 

 Pishes."* By H. M. Kyle, M.A., D.Sc., St. Andrews Univer- 

 sity. Communicated by Professor McIntosh, F.B.S. Ke- 

 ceived June 25, — Eead December 12, 1901. 



Introduction. 



It has been known for some years that the Irish peasantry employ ed 

 a simple method of procuring salmon and trout through the agency of 

 the Spurge (E. hiberna, L.). The plant cut into small pieces and 

 pounded with stones, or simply trampled upon at some convenient 

 spot on a river, forms an emulsion in the water which, being swept 

 downward into the pools, carries death to all fishes in its course. 

 The fatality thus produced seems to have been enormous — 80 to 100' 

 salmon are reported to have been killed at one time,f and again in 

 the Bandon rivers 500 to 1000 fish of various descriptions are said to 

 have been poisoned during one season.]: In the light of the experi- 

 ments to be recorded presently, these statements do not seem exag- 

 gerated, for the Spurge-extract, even in small quantities, is almost as. 

 fatal to fishes as corrosive sublimate. 



The fatal effect of the Spurge on fishes has been known in other 

 countries besides Ireland, but to what ingredient or ingredients of the 

 plant these effects are due seems never to have been investigated. The 

 following pages contain a brief record of experiments which, though 

 incomplete in many ways, throw considerable light upon the action o£ 

 the Spurge, and open out to view some interesting problems. 



As the range of this research has included within its scope several 



* The Fishmongers' Company generously gave a sum for the carrying out of this* 1 

 research. Special thanks are also due to the Hon. Gr. W. Hely Hutchison, secretary 

 to the Irish Inland Fisheries Commission, who forwarded plants of Spurge from. 

 Ireland. 



f ' Report of the Inspectors of Irish Fisheries,' 1898, p. 193. 

 X Ibid., 1892, p. 53. 



