132 EXPERIMENTAL EVOLUTION LECT. 



there appear, on the contrary, an increase in excita- 

 bility and tetanic convulsions. But after two or three 

 days the symptoms become similar in both species. 



Pilocarpin, also, acts differently on the two above- 

 mentioned species, as Harnack and Meyer have 

 shown. 1 In Rana temporaries, pilocarpin induces 

 paralysis ; in R. esculenta, tetanus. Nicotin induces 

 convulsions, followed by paralysis, in esculenta, 

 while- paralysis is the immediate result in temporaria. 

 Similarly, pyridin induces tetanus in esculenta, 

 and in temporaria the symptoms resemble those of 

 picrotoxin poisoning. L. Wintzenried has con- 

 firmed Monnier's results on the different influences 

 of brucin, 2 and Vulpian, 3 in a later paper,, investi- 

 gated the accuracy of the statements of both to his 

 complete satisfaction. Lastly I may be allowed to 

 quote a few lines from a paper by Messrs. Lauder 

 Brunton and Cash, 4 which bears very exactly on the 

 topic : " Johannsen [who was working under Schmie- 

 deberg's direction] observed in the frogs with which he 



1 Harnack and Meyer, Untersuchungen it. d. Wirkungen des fabor- 

 andialkaloide, nebst Bemerkungen u. d. Gruppe des Nicotins. Arch. /. 

 Exp. Path, und Pharm. 



2 Recherches Experimentales relatives a V Action Physiologiqite de la 

 Rrucine. Thesis, Geneva, 1882. 



3 Lemons sur V Action Physiologique des Substances Toxiques et Medica- 

 menteuses. 1882. 



4 Lauder Brunton and J. Th. Cash, On the Circumstances which 

 modify the Action of Caffeine and Theine upon Voluntary Muscle. 

 Journal of Physiology, vol. ix. p. 112, 1888 



