328 Mr Stark on Changes in the Colour of' Fishes. 



much paler than usual. As the white basin stood in the shade, 

 it occurred to me, that, by putting the basin and the animals in 

 the dark, I might be able, on the principle of blanching vege- 

 tables, by excluding them from the light, to render the loss of 

 colour complete. I was not aware at the time that I could with 

 equal ease restore the colours, and in a very short period, to tlieir 

 original brightness and beauty, by a process equally simple. 



June 26. 1830. — I put two minnows which had lived with me 

 over the winter into a white stone-ware ewer. They had at this 

 period the usual vivid colours, back dark brown, and the bars 

 on the upper part of the sides black, upon a silvery ground, with 

 violet and golden reflections. 



June 27. — Upon examining the minnows this morning, I 

 found that they had nearly lost their colour. The back was 

 now of a light sand colour : the bars on the sides had entirely 

 disappeared, and the sides and belly were nearly of one colour, 

 a silvery white, with a shght shade of blue. 



June 28. — Same as yesterday, but the body seemed partly 

 translucent, so that the layers of muscle on the back were dis- 

 tinctly seen, and the vessels between them ; the snout and top 

 of the skull more transparent than usual. 



June 29- — Replaced the minnows in the glass-vessel from 

 which they were originally taken. Appearances same as yester- 

 day. I wrapped a black silk handkerchief round the vessel. 



June 30. — Colours were this morning but little altered from 

 yesterday. Removed the handkerchief, and put them in sun- 

 shine for a few minutes, and placed the bottle upon a black 

 cloth exposed to the light, but not within the rays of the sun. 

 At 4 o'clock p. M. they had regained much of their original co- 

 lours. I now transferred them again into the white ewer. 



July 1. — The minnows have again lost their colour, and be- 

 come totally of a pale sand colour. After examining them, I 

 now placed the ewer in a dark corner of the room, and they were 

 kept in this situation till the 17th July, their colour remaining 

 uniformly pale, and without variation all that time. 



July 17. — I now transferred the minnows to a black glazed 

 earthen-ware jar. In five minutes, dark-coloured spots began 

 to appear on the back ; and in little more than a quarter of an 

 hour they had lost their transpai'ency. Five hours afterwards. 



