1901.] Spurge (Euphorbia hiberna, L.) on Salmonoid Fishes. 59 



1 



Strength and | 



Period 



Animal 



Mode of 





nature of 



within which 



expert 



applica- 



JSotes. 



solution. 1 



it is fatal. 



mented on. 



tion. 





*4 c.c. of do. 



"3 c.c. of do. 



10 per cent, 

 of do. 



10 per cent, 

 of do. 



*01 per cent, 

 tannic acid 



O'l per cent, 

 tannic acid 



6 hours 



3k hours 



2 hours 



1 how 



1 hour 



Trout 



Do. 



Trout 

 post- 

 larval 



Do. later 

 stage 



Do. 



Injected 

 into ab- 

 domen 



Do. 



Animal 

 immersed; 

 in solu- 

 tion 



Do. 



Do. 



Trout, 

 post-larval 

 (later 

 stage) 



Animal 

 immersed 

 in solu- 

 tion 



After 2 hours dimin- 

 ished sensibility shown, 

 but this passed off later. 

 Breathing heavy and 

 deep with gulping move- 

 ments of jaws inter- 

 mittently. In 2nd and 

 3rd colour became very 

 dark, with the red spots 

 more conspicuous ; for 

 post-mortem examina- 

 tion, vide p. 63. 



Weak solutions of Spurge 

 and tannin had little 

 apparent effect upon early 

 stages of trout. The 

 circulation was hardly 

 affected. In later stages 

 stasis was shown in the 

 capillaries at tip of noto- 

 chord and in pseudo- 

 branch of gill-cover. 

 Over yolk-sac and body, 

 however, circulation 

 maintained. This both 

 in Spurge solution and 

 in tannic acid. 



Heart - beats increased 

 from 50 to 60 when at 

 rest and 80 to 85 when 

 active to 90 to 110 per 

 minute. Later fre- 

 quency fell to 80, and 

 then became gradually 

 slower until death oc- 

 curred. Gulping move- 

 ments of the jaws fre- 

 quent, synchronous, or 

 almost so, with failure 

 of ventricular beat. 

 Heart continued to beat 

 feebly for some minutes 

 after circulation in body 

 had ceased. 



If we turn now to the action of the Spurge on fishes, we shall find 

 that the theory which has accounted for its action on frogs renders 

 it possible to understand a series of complex phenomena, which at 

 first sight are very puzzling. Fishes, unlike frogs, are extremely 

 " nervous " animals, and they display symptoms of fright or excite- 

 ment, which must be carefully distinguished from those really due to 

 the Spurge. The details of the experiments are given in the annexed 



