THE LUCKY PROACH. 99 



water, while, on the other hand, the common loach, 

 and several other well known species, die quickly 

 when removed from their native element, although 

 their gills are scarcely at all exposed, the apertures 

 being very small. M. Fleurens, a French physio- 

 logist, has assigned another reason than desiccation 

 for the death of a fish out of water. " If its motions 

 be attentively watched, it will be seen, that although 

 the mouth be opened and shut continually, and the 

 gill-cover raised alternately, the arches supporting 

 the branchiae, or gills, are not separated, nor are 

 the branchial filaments expanded, all remain in a 

 state of colapse ; the intervention of a fluid is abso- 

 lutely necessary to effect their separation and ex- 

 tension, without it these delicate fibres adhere to- 

 gether in a mass, and cannot in that state receive 

 the vivifying influence of oxygen ; the situation of 

 the fish is similar to that of an air-breathing animal 

 enclosed in a vacuum, and death by suffocation is 

 the consequence. To this may be added, that the 

 duration of life in each species, when out of water, 

 is in an inverse ratio to the necessity of oxygen." * 



The Lucky Proach, though disesteemed in Bri- 

 tain as an article of consumption, forms a favourite 

 diet in Greenland, where it often constitutes the 

 principal food of the natives, the soup made from 

 it being both pleasant and nutritious. 



We come now to the genus Gasterostem, of which 

 the species familiarly known under the name of 

 Stickle-backs (Scotice, Benticles), are small fishes, 



* BRITISH FISHES, i. 67. 



