122 



DESIGN IN NATURE 



to, or identical with, ordinary ultra-violet light, with the difference that the wave lengths of the X-rays are very 

 greatly reduced as compared with those of any ultra-violet rays hitherto observed. It is just possible that t e 

 Rontgen rays are cathode rays modified. 



In order to obtain good Rontgen ray photographs, a high electro-motive force is necessary, and the exhaustion 

 of the air must also be carried to a high pitch. It is all but certain that the radiations which characterise the Rontgen 

 rays proceed from the soUd body upon which the cathode rays impinge. " One of the most successful forms ot 

 Crookes tubes for producing the Rontgen photographs is the so-called focus-tube. The method of studying the 

 effects of the X-rays by means of fluorescent screens is more expeditious than that of photography. A fluorescent 

 screen is simplv a sheet of pasteboard covered with a fluorescent substance. Edison has discovered that crystalhsed 

 tungstate of calcium is highly fluorescent. A pasteboard covered with this substance forms the closed end ot a 

 box into which one looks, the hand or limb being pressed against the outside of the pasteboard screen, the 

 fluorescent substance being on the side at which one looks-that is, inside the box. By means of such a fluoroscope 

 one can see the shadow of one's hand after the X-rays have passed through several doors, and at a distance 

 of at least fifteen feet from the Crookes tube. Sensitive photographic plates are fogged through brick walls a 



foot thick." 



The cathode and Rontgen (X) rays, mysterious and inexphcable as they are m many respects, find a parallel 

 in the extraordinary N-rays, as described in 1904 by M. Jean Becquerel to the French Academy of Sciences. 

 The N-rays are emitted by human and other living bodies, and also by certain inanimate substances, in particular 

 by metals. Animals put imder chloroform, it has been ascertained, cease altogether to emit the rays—the 

 emanation recurs when the effect of the anaesthetic has gone off. Death causes final cessation of the emission of 

 the N-rays. Flowers, from which also the rays emanate usually, have been subjected to chloroform and Ukewise 

 went to sleep, the emission ceasing, but recommencing after a time, presumably when the influence of the anaes- 

 thetic had disappeared. This is a sufficiently remarkable phenomenon, but it is nothing to what follows. Similar 

 experiments have been made with the inanimate substances which possess the property of giving out the N-rays, 

 and it is averred that those substances behave exactly as do animate beings under the same conditions. That is 

 to say, a metal emitting the rays in a normal state ceases to emit them when subjected to chloroform vapouis. In 

 short, anaesthetics will apparently cause metals as well as flowers and animals to sleep. It has yet to be deter- 

 mined whether metals (to speak figuratively) can be killed permanently by the continued administration for a 

 given time of anaesthetics and other poisons in the same way that plants and animals can. If M. Becquerel's 

 statements be confirmed, justification in part will be found for them in the fact that quite a large percentage of all 

 the known elements (particularly the metals) is found in the bodies of plants and animals. 



The new theory involves questions of very considerable magnitude, namely, the nature and range of fife. It 

 will naturally be asked in the near future, Can the term life be confined exclusively to plants and animals, or must 

 it be expanded to include certain so-called inanimate substances ? Hitherto, and by common consent, life has 

 been regarded as forming the distinguishing feature between the organic and inorganic kingdoms ; the members 

 of the organic kingdom living, feeling, and moving, those of the inorganic kingdom moving, but neither hving 

 nor feeUng. While it will require much additional observation and experiment to establish the new doctrine, it 

 would be premature at present to affirm that it is a wholly impossible doctrine. Like other new doctrines, this 

 latest physico-physiologioal departure is on its trial, and will have to be corroborated by independent workers in 

 kindred fields, and sufficient time allowed to test the accuracy of the theory in relation to known phenomena. 



Striking specimens of hghtning, electric sparks, and cognate subjects are given in Plates xxix. to xxxiii. 



ANIMAL MAGNETISM 



The electric fishes are endowed with extraordinary powers, and deserve more than a passing notice. 



They are mostly found in tropical and sub-tropical regions, and although not numerous, are not confiined to 

 any one family of fishes. They are, moreover, not the exclusive product of modern times ; their fossil remains 

 proclaiming them old-world forms. They are smooth-skinned — that is, they are not covered with scales as other 

 fishes. The electricity which they generate in their bodies in every respect resembles ordinary electricity, and 

 is completely under their control. They can discharge it in small or large quantity, and at pleasure, either in 

 defence or in attack. In certain oases, and under provocation and excitement, the shock transmitted is sufficient 

 to disable or even kill a man. The electrical organs are elaborate structures, and have a remarkably bountiful 

 nerve supply. They have also an ample blood supply. The very numerous and large nerves extending between 



