G2 



KNOWLEDGE 



[Jan. 23, 186 5. 



secondly, below these, another pair, also capable of lateral 

 motion, the ma.vi/he. Add finally a pair of jointed appen- 

 dages attached to the base of the maxillce, and another pair 

 to the labium (which is essentially a second pair of maxilla), 

 the maxUlary and labial pa^pi, and you have the main 

 parts of that complicated mtchanism with which insects 

 have to take their food. Many of these parts are often 

 modified to an extreme degree, and more or less depiived 

 of their power of motion, and some nay be altogether 

 suppressed ; still, a careful examination will usually enable 

 the above jilan to be more or less easily recognised. 



Fig. 2. — Ucad of Female Gnat, much magnified. a, Antenna ; 

 b labrum ; r, mandibles ; d, maxillEe ; e, lingua; /, labium ; g, maxil- 

 lary palpus. 



Now, in our gnat (Fig. 2) the labrum is transformed into 

 a stout bristle, and the labium elongated to an extraordi- 

 nary degree, forming a sort of sheath, open above and 

 sheltering in its trough both mandibles and maxillre ; the 

 whole apparatus forms a kind of snout or proboscis nearly 

 half the length of the animal's body. The mandibles, 

 instead of being jaw-like, and working upon one another 

 like the blades of a pair of scissors, are transformed into 

 two long, slender bristles, exceedingly sharp-pointed and 

 barbed at the tip, like a savage's spear — a pair of most 

 murderous weapons. The maxillre, too, are bristles, more 

 slender than the mandibles, and equally sharp-pointed ; 

 their palpi are easily recognisable as jointed organs visible 

 outside the beak. 'There is yet a fifth extremely fine hair- 

 like lancet, the representative of an organ which appears in 

 many insects as a prolongation of the central portion of the 

 labium, and is called the lingua, or tongue. Labial palpi 

 are absent. All these five lancets lie neatly packed away 

 in the sheath-like labium, and so completely are they con- 

 cealed that you would never guess that it contained such a 

 collection of instiuments of torture. Now for the surgical 

 process by which the little villain obtains its food. We 

 must, however, first acquit half the gnat household of 

 bloodthirsty propensities ; the male does not seem to be pos- 

 sessed of these stilettos ; he is a mild, inoffensive creature, 

 who generally confines himself to his native swamps, and 

 does not invade the privacy of our apartments ; but his 

 spouse is a veritable virag'i, and boldly intrudes even into 

 our bedchambers, with the view of obtaining an evening 

 repast from the unconscious lord of creation, who lies 

 calmly sleeping within. Gently she alights on some ex- 

 posed portion of her victim, resting on her four front legs, 

 and daintily elevating the other p.air into the air behind 

 her ; then she bring her needle-case down on the point 

 chosen for attack, and, forming her needles into a single 

 boring-organ, pushes them through the skin, apparently 

 without much ditEculty, till at length she reaches the blood 

 of the sleeper, which is then sucked up the interstices 

 between the bristles till the little phlebotomist is gorget^. 

 The irritation caused by these operations is often so great 

 that it has been supposed that prison is injected into the 

 wotind ; but no poison glands have been detected, and it 

 would seem probable that the incisions themselves are a 

 sufficient cause of the inflammation and consequent irri- 

 tation. 



The Chironomidf, or midges, diflfer but little from the 



gnats, save in the mouth apparatus, which is not prolonged 

 into a beak, and is altogether much simpler. They are also 

 unprovided with scales. 



{To te continued.) 



OUR TWO BRAINS. 



By Eichard A. Peoctob. 



(Contimied from p. 22.) 



IT will be observed that the cases of dual consciousness 

 thus far considered, though alike in some respects, 

 present characteristic divergences. In that of the boy at 

 Norwood, the two characters were very similar, so far as 

 can be judged, and each life was distinct from the other. 

 The next case was only introduced to illustrate the re- 

 semblance in certain respects between the phenomena of 

 somnambuli.'m and those of double or rather alternating 

 consciousness. The woman Felida X. changed markedly 

 in character when she passed from one state to the other. 

 Her case was also distinguished from that of the boy by 

 the circuHjStance that in one state she was conscious of 

 what had passed in the other, but while in this other state 

 was unconscious of what had passed in the former. Lastly 

 in Sergeant F.'s case we have to deal with the effect of an 

 injury to the brain, and find a much greater difference be- 

 tween the two conditions than in the other cases. Not 

 only does the man change in character, but it may justly 

 be said that he is little more than an animal, even if he 

 can be regarded as more than a mere automaton while in 

 the abnormal condition. We find that a similar variety 

 characterises other stories of double consciousness. Not 

 only are no two cases closely alike, but no case has been 

 noted which has not been distinguished bj' some very marked 

 feature from all others. 



Thus, although in certain respects the case we have next 

 to consider resembles very significantly the case of Sergeant 

 F., it also has a special significance of its own, and may 

 help us to iiiterpret the general problem presented to lis by 

 the phenomena of dual consciousness. I abiidge, and in 

 some respects simplify, the account given by Dr. Carpenter 

 in his interesting treatise on " Mental Physiology." Com- 

 ments of my own are distinguished from the abridged narra- 

 tive by being placed within brackets : — 



A young woman of robust constitution had narrowly 

 escaped drowning. She was insensible for six hours, and 

 continued unwell after being restored to animation. Ten 

 days later she was seized with a fit of complete stupor, 

 which lasted four hours ; when she opened her eyes she 

 seemed to recognise no one, and appeared to be utterly 

 deprived of the senses of hearing, taste, and smell, as well 

 as of the power of speech. Sight and touch remained, but 

 though movements were excited and controlled by these 

 senses, they seemed to arouse no ideas in her mind. In 

 fact, her mental faculties seemed entirely suspended. Her 

 vision at short distances was quick, and the least touch 

 startled her; but unless she was touched or an object were 

 placed where she could not help seeing it, she took no 

 notice of what was passing around her. [It does not appear 

 to me certain that at this stage of her illness she sau- in the 

 ordinary sense of the word ; the sense of touch may alone 

 have been affected, as it certainly is aflfected to some degree 

 by any object so placed that it could not It.I he seen by a 

 short sifjliled person. But it is clear that later the sense of 

 sight was restored, supposing, which is not perhaps probable, 

 that it was ever lost in the early Et?ge.] She did not even 

 know her own mother, who atten':'ed c?nstantly upon her. 



