378 OBSERVATIONS AND EXPERIMENTS 



pectoral fins, and by supporting- the tail on near objects. At the 

 same time they breathed extremely fast, half water, half air, with 

 the upper jaw out of the water. They expelled the water mostly 

 from the mouth, more rarely from the gills, so that at each breath 

 they threw up bubbles, and soon a wreath of foam of large bubbles 

 surrounded them. Many fish, among others the Gymnotus 1 , rise to 

 the surface to take in air, but this throwing up of bubbles was 

 recognised by our keeper Graff as a sign of distress and weakness 

 in fishes. Malapterurus in this condition no longer discharged on 

 being touched ; the barbels were no longer stretched out in straight 

 lines, the skin became wrinkled and ulcerated ; blood issued from 

 the fins and the gill-covers ; sometimes at last a violent motion 

 convulsed the jaws and gills. Fish so affected inevitably died. 

 Aeration of the water by means of bellows remained without 

 result. Such fish ought to be used systematically in good time for 

 experiments, instead of delaying, as I unfortunately often did, until 

 they were found dead, in which case it is not only impossible to 

 experiment, but the event may be observed so late, that the fish are 

 useless even for histological purposes. One can, however, be never 

 quite secure against this mishap, for the fish may die without clear 

 premonitory symptoms, and as they generally lie quiet deep down, 

 their death may remain unnoticed so long, that nothing more can 

 be done with them. 



4. Mode of experimenting with living Malapterurus. 



After the above experience there is no doubt that of the three 



electrical fishes, the Malapterurus is the best fitted to be kept in 



confinement. The Torpedo, as an inhabitant of the sea, cannot bear 



comparison with it 2 ; the Gymnotus, while it can be kept equally 



1 Comp. Edw. Bancroft, An Essay on the Natural History of Guiana, London, 

 1879, p. 192. 



Hugh Williamson, Philosophical Transactions, etc., 1775, p. 94; Alex. Garden, 

 ibidem, p. 102 ; Humboldt, Kecueil d' Observations de Zoologie et d'Anatomie 

 compare'e, etc., Paris, 1811, 4. p. 61 ; Faraday, Experimental Kesearches in Elec- 

 tricity. Keprinted from the Philosophical Transactions, etc., vol. ii. London, 1844, 

 p. 3. Ser. XV. 1753. (The paper, frequently quoted in the following, by Faraday, 

 upon the electric eel, is also found in Poggendorft's Annalen, etc., 1842, Ergiinzungs- 

 band, p. 391.) 



2 Until the formation of zoological stations, no one in my knowledge has succeeded 

 in keeping the Torpedo alive longer than fifteen days, and John Dary is the only one 

 who was so fortunate. (Researches physiological and anatomical, London, 1839, 

 vol. i. p. 48; comp. Faraday, Experimental Researches, etc., loc. tit. p. 2, 1752.) 

 John Todd, who made his observations at the Cape of Good Hope, and therefore 

 presumably on Astrape Capensis Mull. Henl., (Philosophical Transactions, etc., 1816, 



