THE MINNOW. 137 



crimson and carmine on the sides and belly. The eye also assumes a 

 brilliance of crimson which is unspeakably beautiful, and the voracity of 

 the fish seems doubled. The head and scales but especially the head 

 become covered with tiny tubercles, which disappear immediately after 

 spawning. The operation does not occupy more than three days, and the 

 growth of the fry is exceptionally rapid. During spawning time the 

 parent fishes often at night time glow with marked phosphorescence. 



Although not to my knowledge cannibalistic or pugnacious, the minnow 

 is decidedly voracious. They live on minute water insects and minute 

 vegetable organisms, which, on microscopic examination from some 

 waters, exhibits a long list of remains of animalcules and other debris 

 more or less capable of identification. The little fellows are hardy, and 

 seem to thrive best in rather hard water. Mr. Pennell says that they 

 will not live over three years. This is an error, for I have ample proof 

 that five and six years are not excessive instances of longevity. 



I have before referred to the difference which the pigment of the skin of 

 various fishes presents, according to the colourable characteristics of the 

 waters from which they are taken and the state of the health of the fish. 

 Thus a perch will vary from a light dusky striped brown to a deep olive, 

 and trout also vary in a similar manner. In reference to the latter fish, 

 Sir Humphrey Davy says, ' ' the colouring matter is not in the scales but 

 in the surface of the skin immediately beneath them, and is probably 

 a secretion easily affected by the health of the fish," and, of course, 

 these remarks are applicable to any other kind of fresh- water fish at least. 

 In none other is the variation so marked as in the minnow. For the sake 

 of convincing myself of the chameleon-like character of the pigment in 

 question, I made the following experiment : I took five ordinary gallipots, 

 and painted the interiors of four as follows : Black, red, blue, and yellow, 

 the fifth remained untouched, and was, of course, white. Thus I had the 

 three primary colours and their ultimate combinations. The three jars 

 were placed in a row in equal light not sunlight, but light through 

 a frosted pane, and, having filled the pots equally with water from a dark 

 bait cistern, I lifted simultaneously five strong lively minnows, and 

 placed one in each receptacle. The colour of each at this time was uni- 

 formly dark olive on the back. In the course of two hours each specimen 

 presented a different colour, when all were replaced in a black painted 

 can. The fish in the black jar remained unaffected, that in the red was 

 somewhat lighter and clearly mottled, that in the blue rather of a browner 

 tint, that in the yellow of a yellowish dirty-brown hue, that in the white 

 of almost a straw colour. I replaced them during that and the ensuing 

 day in the pots in a different order, varying them once or twice in this way 

 with almost immediate results, which were exceedingly curious. The 



