13 



they were exposed to the electric light for Bix successive nights, 

 beginning when daylight failed, and continuing till sunrise. The 

 plants had thus no rest, but they did not suffer. The experiment 

 was next tried in the open air, with successful results, and the 

 invigorating effect of electric light and sun-shine combined was 

 very marked. 



It still remained to be seen whether the electric light would 

 aid in ripening fruit. Dr. Siemens therefore tried its effect ujjon 

 strawberries. He took two pots of strawberries started under 

 precisely similar conditions. One was exposed to dayhght only 

 in the usual way, and showed a bunch of green berries ; while the 

 other which, in addition to daylight, had been under the electric 

 light during the night, bore a cluster of ripe, large, well-flavoured 

 berries. Thus demonstrating that electric light promoted the 

 formation of the saccharine and aromatic substances on which the 

 ripening and flavour of fruit depend. 



While we have thus spoken of light as affecting the life and 

 growth of plants, we must not forget that there are some species 

 of fungi which may be classed as light-giving. One of the best 

 known of such species is the Agaricus olmrius, which was some 

 years since the subject of a monograph by Tulasne, published 

 under the title " Sur la Phosphorescence de Champignons," (Ann. 

 des Sci. Nat., vol. ix. p. 338). At first it was conjectured that 

 such phosphorescence was developed ot^ly at the time of decompo- 

 sition ; but further obseiTations have so far changed this opinion 

 that now some assert the fungus is phosphorescent only during 

 growth ; that when it ceases to gTow, it ceases to shine. This light 

 is of a pale bluish colour resembhng that emitted by phosphorus 

 in a dark room. 



Let us now turn to the animal world and briefly trace some 

 of the influences of light upon its members. 



By far the larger number of animals are conscious of light by 

 means only of the eye. There are but few back-boned animals 

 absolutely without eyes. Moles, the Proteus, and the blind fish, 

 as they are called, of the American caves {Amhlyopsis Spelcens, 

 etc.) have all rudimentary eyes; and in most ca.ses the condition 

 of the eye in such animals is one of degeneration, the development 

 of the organ being arrested at an almost embryonic stage; while, 

 as the animal attains maturity, the eye being small, deeply im- 



