354 



• KNOWLEDGE ♦ 



[Oct. 31, 1884. 



rounded leaves, often with no perceptible lobes, and some- 

 times almost circular in shape. 



Why is ivy evergreen 1 I believe for this reason. It is 

 not a plant of very cold countries : it won't grow in North 

 Germany, Russia, or Siberia, and Britain is almost its 

 nortliern limit. Southern Europe, Northern Africa, and 

 Western Asia are its favourite dwelling-places. In the 

 wild state, it is chiefly a woodland plant, clambering up the 

 trunks of trees in the great forests. Hence it is shaded 

 during a greater part of the year by the leaves on the 

 deciduous trees, and it has to lay by the material for its 

 growth and flowering and fruiting in autumn, winter, and 

 spring, when the boughs above have lost their foliage. As 

 a matter of fact, even in England, its growth is most 

 luxuriant in late autumn, it flowers in October and 

 November, it goes on putting forth fresh leaves and wood 

 as long as the season permits it, it ripens its berries through 

 the winter, and it begins leafing again as soon as the spring 

 is once more with us. In more southern countries it 

 works uninterruptedly from October to May, and lies by 

 almost dormant during the long dry summer. It is thus 

 essentially a winter plant, and that, I take it, is why its 

 leaves are evergreen. 



The curious and pretty yellowish green flowers are worth 

 a moment's consideration. They have each five small 

 petals, and five stamens, with a very broad disk in the 

 middle, surrounding the central stigma. This disk secretes 

 quantities of honey, which stands in little drops upon its 

 surface, and can be readily distinguished with the naked 

 eye and tested with the tongue. The honey attracts 

 large numbers of flies, bees, and wasps, but especially 

 the hive-bee, which, in England at least, is certainly 

 (so far as I have noted) the chief fertiliser, though 

 Continental observers give this rule in Italy and France 

 to the flies and beetles. The stamens mature first, so 

 as to prevent fertilisation from the same flower ; and in 

 this state the petals are simply expanded, and the honey 

 abundant. Bees visiting such flowers carry away pollen on 

 their heads for the next they visit. Afterwards the 

 blossoms reach their second state, the petals roll backward, 

 the stigma ripens, and the honey decreases greatly in 

 quantity. Bees visiting these maturer flowers rub ofi' upon 

 them the pollen they have brought from the ripe stamens 

 of neighbours in their first state. Inconspicuous as the 

 blossoms are, individually, their habit of massing in large 

 clusters, and their smell of honey, seem to stand them in 

 good stead of brilliant petals ; for they are much resorted 

 to by all the insects that still fly about in late autumn. 



After fertilisation, the berries begin to grow as best they 

 may thro\igh the winter ; but they do not ripen or assume 

 their bluish-black tint till the next year. They are then 

 much eaten, and their seeds dispersed, by birds, which find 

 these dusky hnes very attractive, as in the sloe, the black- 

 berry, the whortleberry, and the privet. A southern variety 

 in our gardens, however, has prettier berries of a bright 

 yellow colour. 



OUR TWO BRAINS. 

 By Richard A. Proctor. 



(Continued from p. 310.) 



BUT perhaps the most remarkable illustration of a 

 double life is one which was brought before the 

 notice of the scientific world a few years ago. I refer to 

 the case published by Dr. Mesuet, and mentioned in Dr. 

 Huxley's remarkable lecture at Belfast on the hypothesis 

 that animals are or may be automata. I do not purpose to 



quote Huxley's account in full, as no doubt many of my 

 readers have already seen it, but the following facts are 

 necessary to show the bearing of the case on Sequard's 

 theory : " A sergeant of the French army, F — , twenty- 

 seven years of age, was wounded at the battle of Bazeilles, 

 by a ball which fractured his left parietal bone. He ran 

 his bayonet through the Prussian soldier who wounded 

 him, but almost immediately his right arm became para- 

 lysed ; after walking about two hundred yards his right 

 leg became similarly affected, and he lost his senses. 

 When he recovered them, three weeks afterwards, in 

 hospital at Mayence, the right half of the body was com- 

 pletely paralysed, and remained in this condition for a 

 year. At present, the only trace of the paralysis which 

 remains is a slight weakness of the right half of the body. 

 Three or four months after the wound was inflicted, 

 periodical disturbances of the functions of the brain made 

 their appearance, and have continued ever since. The 

 dLsturbances last from fifteen to thirty hours, the intervals 

 at which they occur being from fifteen to thirty days. 

 For four years, therefore, the life of this man has been 

 divided into alternating phases, short abnormal states 

 intervening between long normal states." 



It is important to notice here that although this case 

 somewhat resembles that of Brown-Sequard's two-lived 

 boy, we have in the soldier's case a duality brought about 

 by a difierent cause, an accident affecting the U/'t side of 

 the head — that side, as we shall presently see, which is 

 regarded as ordinarily if not always the seat of chief intel- 

 lectual activity. The soldier's right side was paralysed, 

 confirming the theory that so far as the bodily movements 

 are concerned the left brain chiefly rules the right-hand 

 organs of the body, and vice versd. But the man had 

 recovered from his paralysis, so that either the left side of 

 the brain had been partially restored or else the right brain 

 had acquired the power of directing the movements of the 

 right-hand organs. But the periodical disturbances came 

 on three or four months after the wound was inflicted, 

 that is, more than half a year before the paralysis dis- 

 appeared. We have, then : 1st, three weeks of unconscious- 

 ness, during which we may suppose that the left side of 

 the brain was completely stunned (if ws may apply to the 

 brain an expression properly relating to the condition of 

 the man) ; secondly, we have three months during which 

 the man was conscious, and in his normal mental condition, 

 but paralysed; thirdly, we have more than half a year 

 during which a double mental life went on, but the left 

 side of the brain was still so far affected that the right 

 side of the body was paralysed ; and lastly, we have more 

 than three years of this double mental Ufe, the bodily 

 functions in the man's normal life being, it would appear, 

 completely restored. 



Assuming, then, Wigan's theory for the moment, we 

 have to inquire whether the man's normal condition implies 

 the action of the uninjured right brain, or of the restored 

 left brain, and also to determine whether the recovery from 

 paralysis has resulted from a more complete restoration of 

 the left brain, or from the right brain having acquired a 

 power formerly limited to the left brain. The fact that 

 the man's normal mental condition returned as soon as 

 consciousness was restored does not show that this condi- 

 tion depends on the action of the left brain, for in the 

 unconscious state both brains were at rest. Rather it 

 might seem to imply that the right brain was the brain 

 active in the normal mental state, for the continued paraly- 

 sis of the right side showed that the left brain was not 

 completely restored. Yet it has been so clearly .shown by 

 other and' independent researches that the left brain is the 

 chief scat of intellectual activity that we seem forced to 



