1882.] 



AND HORTICULTURIST. 



diseased is not the virus produced by bacteria ; 

 but the poison originates in vitiated sap. Now, 

 this sap is simply that which has accumulated in 

 (fee tree and its branches since the fall of the 

 leaf, and has not been aerated, but frozen and 

 devitalized during the winter. Remaining in 

 the tree in spring, it clogs the channels and dis- 

 turbs the whole economy of the structure. 

 Warm weather and a mingling of this inert 

 fluid with the active sap causes a great increase 

 of bacteria— the operating principle in all fer- 

 mentation — and when the disease reaches a cer- 

 tain stage it becomes apparent in suddenly 

 blackened leaves and withering branches. This 

 is the only theory that can satisfy all the re- 

 quirements of the case. 



There must be some error about bacteria 

 abounding in the circulatory vessels of human 

 beings. They are not in the blood, and can be 

 found nowhere but in the large intestines. In- 

 fusoria are, doubtless, in the human body, but 

 they possess an independent motion, and differ 

 widely from bacteria. 



THE INFLUENCE OF ELECTRIC LIGHT 

 ON PLANTS. 



Translated for the GARDE>fER's Monthly from the 

 Berliner Tribune. 



BY S. M. 



How much of human progress we would miss 

 if we could not master electricity ! As it is, 

 epace and time are almost annihilated, and elec- 

 tricity begins even to compete now with the sun. 

 Night is transformed into day, and that time 

 may not be distant when every steamer, crossing 

 the ocean, will carry its electric sun to chase 

 away the terrors of the night. In this line elec- 

 tricity seems likely in future to substitute the 

 sun also for the field and the garden, and may 

 attain an incalculable importance. 



We have heretofore been told that the benefi- 

 cent influence of alternating day and night on 

 us mortals is effected both through the change 

 from activity to rest, and from light to darkness 

 Our eyelids would not droop so easily, and sleep 

 would not be so refreshing if the stimulus of 

 light were uninterrupted. We are likewise in- 

 clined to believe that the repose in darkness is 

 necessary for plants, as though it were a rest 

 from the stimulus of the light of day. Closely 

 considered, we find that the change from day to 

 night is after all but a relative one on our plan- 

 et, and subject to the widest variations. On 

 one hand, the constantly equal length of night 



and day under the Equator ; on the other hand, 

 night of six months' duration at the poles, and 

 all the gradations between. This would seem to 

 prove that, as a general principle, the alterna- 

 tion of day and night would not be necessary for 

 plants, and the investigations of Mr. C. W. 

 Siemens, in London, would almost make sure 

 that many plants at least not only can stand 

 constant light, but will improve under it in 

 growth. 



As long as eighteen months ago, Mr. Siemens 

 already published his experiments on the influ- 

 ence of electric light on vegetation, and they 

 showed that its effects on plants were similar to 

 sunlight, that they formed chlorophyll (leaf- 

 green) ; that, under it, blossoms and fruit, odor- 

 iferous and savory, were developed — in fact, 

 that a periodical withdrawal of light during the 

 twenty-four hours was not generally neces-snry, 

 but that, on the contrary, many plants would 

 grow stronger and richer if, in winter-time, (ex- 

 posed by day to sunlight, by night to electric 

 light. 



Since then Mr. Siemens has continued his in- 

 vestigations on a larger scale, and they claim so 

 general an interest, that it seems proper to spoak 

 about them here, after his report read last Spp- 

 tember before the British Association. 



Mr. Siemens used two electric lamps, worked 

 by the currents of two electro-dynamic ma- 

 chines, each supplying the light of four thousand 

 candles. One lamp was hung inside of a glass 

 house of 2,318 cubic feet of space, over the en- 

 trance, and a metallic reflector was fixed bet': re 

 it for the purpose of collecting its rays and turn 

 them on the plants, which otherwise would have 

 lost them. The other lamp was hung in the 

 open air, twelve to fourteen feet high over some 

 low-situated glass houses. These experiments 

 lasted from the 23rd of October, 1880, to the 7lh 

 of May, 1881. The electric light glowed from 

 six in the evening, and, during the shorter 

 days, from five in the evening. The only 

 rest given the plants was during Sundays. 

 There were peas, string beans, wheat, barley, 

 oats, cauliflower, raspberries, strawberries, 

 peaches, golden apples (tomatoes?) grapes, 

 and some flowers, such as roses, Rhodo- 

 dendrons and Azaleas. The lamp in the 

 open air had a glass shade, the lamp inside had 

 none. The effect of the two lamps immediately 

 showed a great difference. The plants under 

 the first prospered exceedingly; under the 

 second they soon got to look wilted. But as 



