December 2, 1895.] 



KNOWLEDGE. 



285 



and discharged by the mistle or, rather, mistletoe thrush. 

 Sir Thomas Browne, in his " Pseudoxia Epidemica," follows 

 Lord Bacon's sceptical rejection of the ancient theory of 

 mistletoe plant propagation, and, indeed, goes more than 

 one point further. He says ; " Why if it ariseth from a 

 seed if sown it will not grow again, Pliny affirmeth, and 

 as by setting the berries thereof, we have in vain attempted 

 its production ; why if it cometh from seed that falleth 

 upon the tree, it groneth often downward and puts forth 

 under the bouqh, where seed can neither fall nor yet remain," 

 &a. (page 106, edition 1672). 



We have italicized those words of the sceptical doctor 

 upon which he appears to have put most stress as destruc- 

 tive of the ancient theory, although, as a matter of fact, he 

 was at one with Lord Bacon on the other points, and was 

 equally astray. We have seen that a very distinguished 

 German sylviculturist has propagated an entirely erroneous 

 theory to account for the phenomenon that puzzled both 

 Lord Bacon and Sir Thomas Browne. We must appeal to 

 another great German authority to aid us in explainmg 

 the apparent mystery of the undergrowth characteristic 

 of the mistletoe plant. The following passages will be 

 found in Vol. I., pages 205-6, of the new English edition of 

 " The History of Plants," by Anton Kerner von Marilaun, 

 Professor of Botany in the University of Vienna : — 



"The dissemination of the European mistletoe is effected, 

 as in all the other Loranthaceae, through the agency of 

 birds — thrushes in particidar — which feed upon the berries 

 and deposit the undigested seeds with their excrement 

 upon the branches of trees. That a preliminary passage 

 through the alimentary canal of birds is essential to the 

 germination of these seeds is no doubt a delusion, this 

 assumption of former times being easily refuted by the 

 fact that one can readily induce the seeds of berries, taken 

 fresh from a tree and stuck into fissures in the bark of 

 moderately suitable trees, to germinate ; it is, however, 

 true that in nature mistletoe seeds are dispersed exclusively 

 by birds in the manner above mentioned. To this method 

 of dissemination must be attributed the phenomenon, 

 which, at first sight, is surprising, that mistletoe plants 

 are rarely seated upon the upper surface of branches, but 

 very frequently on the sides. For the dung of thrushes, 

 which live upon mistletoe berries, is in the form of a semi- 

 fluid, highly viscid mass, ductile like bird lime ; and even 

 when it is deposited upon the upper surface of slanting 

 branches it immediately runs down the sides, sometimes 

 extending in ropes twenty or thirty centimetres in length. 

 Owing to the viscous mass thus following the law of gravity, 

 the mistletoe seeds embedded in it are conveyed to the sides 

 and even to the under surface of the bark, and there remain 

 cemented. It may be a long time before a seed of the 

 kind germinates, especially if it does not become attached 

 until the autumn. The embryo is completely surrounded 

 in the seed by reserve food. It is club-shaped and com- 

 paratively large, and is distinguished by the fact that the 

 two oblong cotyledons, which are closely pressed together, 

 but often somewhat wavy at the margins, are coloured 

 dark green by chlorophyll, like the environing cellular 

 mass fiUed with reserve materials. In the process of 

 germination, the axis of the embryo, especially the part 

 lying beneath the cotyledons, and passing into the 

 hemispherical radicle, lengthens out, the white seed coat 

 is pierced, and the radicle makes its appearance through 

 the breach. Under all circumstances the emergent radicle 

 is directed towards the bark of the branch to which the 

 seed is adherent. This is the case even when the seed 

 chances to stick with the radicle of the seedling pomting 

 away from the branch, the whole axis of the embryo 

 cui-ving towards the surface of the bark in a very striking 



manner. Thus the radicle always reaches the bark, and 

 having done so it becomes adpressed and cemented to 

 its surface, spreads itself out in the form of a doughy 

 mass, and so develops into a regular attachment disc. 

 From its centre a slender process now grows into the 

 bark of the host plant, piercing the latter and penetrating 

 as far as the wood, but not growing into that tissue. This 

 penetrating process has been termed a ' sinker,' and must 

 be looked upon as a specially modified root." 



In the language of the great German botanist, the whole 

 mystery is cleared up, and the facts now made plain may 

 even go some length in clearing up the philological difficulty 

 about the origin of the words " mistletoe " and " mistle 

 thrush." The theories of Dr. Prior, Bosworth, and others 

 who traced the word to the old English mistiltan, " from 

 'mistl,' different, and 'tan,' a twig, being so unlike the tree 

 it grows on," must be abandoned. It is possibly derived 

 from the Scandinavian " mist," meaning dirt, or obscurity. 

 But be that as it may, we have endeavoured to show that 

 in the realm of pure science there are associations of 

 mystery and romance quite as interesting as the associate 

 ideas of Druidic ceremonial and cult, and almost as 

 fascinating as the legendary significance of kissing under 

 the mistletoe, with all its far-reaching or, it may be, quite 

 ephemeral consequences. Then the bird itself has been 

 the object of much study and an infinity of " fine writing." 

 The habits are now well known, and have been fi-equently 

 described. To our mind, its piercing but sweet strain of 

 music, poured forth in the pauses of a wild February or 

 March storm, possess the additional charm of mystery 

 because, like the music of the robin or the wren, we cannot 

 reconcile such voluntary bursts with the theory of sexual 

 rivalry as the origin of avian song. 



Some 3:icfcnt patents. 



Messrs. R. & J. Beck are introducing a new patent called the 

 Card-case Opera G-lass. This ingenious invention consists of eye- 

 pieces and object-glasses without connecting tubes. It folds up flat 

 into a small space, and weighs only three and a half ounces. The 



lenses are fairly good, and the glass will, no doubt, prove valuable to 

 naturalists amongst others, as it can always be carried about without 

 inconvenience. It would, however, be useless in wet weather, as the 



glasses have no protection. 



»-*^ 



J. B. W. Betts, of Plymouth. An improved apparatus for the 

 production of bauds of colour by the rotation of certain forms of any 

 size, material or shape. This apparatus is intended for the same 

 purpose as the spectrum top noticed in our coliuaus some time ago. 

 It consists of a wheel connected with an upright, on which designs 

 (of different shape- and mai-ked in different ways with black lines) 



