Jan. -n, 1882.] 



KNOWLEDGE 



263 



fusion of thought and inability to fix the attention. " I 

 now wished," proceeds the patient, " to ring for my servant, 

 :uid desired him to inform my wife to come to nie." (The 

 power of correctly expressing his ideas does not seem to 

 liave been possessed in any \-ery remarkable degree by this 

 1,'entleman, even when his mind had fully recovered its usual 

 health). " But I found it still necessary to wait a little 

 longer, to exercise myself in the right pronunciation of the 

 few words I had to say, and the first half-hour's cou\-er- 

 siition r had with her was, on my part, preserved with a 

 slow and anxious circumspection, until at last I gradually 

 found myself as clear and serene as in the beginning of the 

 iluy. All that now remained was a slight headache. 1 

 ■ collected the receipt I had begun to write, and in which 

 knew I had blundered, and upon examining it, I observed, 

 •o my great astonishment, that instead of the words Jijhj 

 lUiUars, behig one half-year's rale, which I ought to have 

 written, the words -wetQ, fifty dollars, throuj/h the salvation 



,/' Bra , with a break after it, for the word ' Bra ' was 



.it the end of the line. I cannot recollect any business 1 

 had to transact that could by means of an obscure influence 

 iiuve produced this phenomenon." 



In this case it is obvious that the temporary loss of the 

 [lower of verbal expression was occasioned )iy overwork ; 

 l>\it it is noteworthy that the work was of a special cliarac- 

 rcr, involving the special exercise of the power which failed 

 •irst (that of fixing the attention). It may be worth while 

 •o inquire whether that kind of mental confusion, which, 

 • hen it has passed beyond a certain point is followed by 

 inpairnient of the power of speech, is generally or often a 

 onsequence of distracting occupations. The following case 

 seems to some degree to bear on this question. It is related 

 by Dr. Watson. A patient who had had an attack of 

 apoplexy seemed to be recovering under the influence of 

 perfect quiet. But, "after a long and imprudent conversa- 

 tion with a friend, he suddenly lost the thread of his dis- 

 course, and could not recover it. ' Memory was aftected first, 

 be it observed : next went the power of attention. "Then he 

 became confused." Thirdly, the power of speech was 

 aflfected. " He misapplied words. I asked him how he 

 felt. He answered, ' Not quite right,' and this he repeated 

 very many times, abbreviating it at first into ' not right,' and 

 and at length into ' n' ight' Wishing to mention ' camphor,' 

 he called it ' jtainphlet.' I mention these as specimens." 

 Afterwards, signs of bodily weakness, indicating paralysis, 

 were observed. The weakness degenerated gi-adually into 

 complete palsy, and before long the case ended fatally. In 

 this case the patient had not suflfered originally from undue 

 mental work, the mental trouble being caused by an 

 abscess. But the case seems to illustrate well the trying 

 effect of distracting conversation on a wearied, weakened, 

 or (as in this case) diseased brain. 



The tendency to use one word for another, where, so far 

 as meaning is concerned, there is no connection whatever, 

 though there is somi! resemblance of sound, is one which 

 probably most literary men have noticed at times, when 

 they have been wearied or theii' attention has been much 

 distracted. It is not by any means so alarming a symptom 

 as temporary failure of the power of articulating words, or 

 actual inability to write the desired words ; but it is a cii'- 

 cumstance which should not be overlooked. A little rest, or 

 the substitution for awhile of some light reading for hard 

 brain-work, will generally set matters right. If not, a longer 

 rest or open-air exercise should be taken. Time will be gained 

 by waiting till the brain is fitter for work. The present 

 writer has repeatedly had occasion to time himself over cer- 

 tain forms of literary work, and his experience has been this, 

 that where four or five hours are to be occupied in steady 

 work, a good half-hour will often be saved by taking half- 



an-hour's sleep, when such signs of mental weariness are 

 noticed as have been described above. There is, however, 

 one point to be observed. Rest must he tiiken as soon as 

 such signs are recognised, for if an eflbrt is made t<:> 

 struggle against the occasion for rest, the power of resting 

 may be lost. Precisely as an over-tired pedestrian often tries 

 in vain to sleep, when he has but a short time, for rest, so the 

 overw(!aried brain may be kept by confusing thoughts from 

 obtaining rest. 



DR. J. W. DRAPER. 



By the Editor. {With a Portrait.) 



A^IONG the distinguislied men whose acquaintance I 

 have made during my lecture tours in this country 

 America, and Australasia, few occupy a higher place in my 

 recollection than Dr. [J. W. Draper, whose death, at New- 

 York, has just been announced. His scientific researches 

 and literary work are justly regarded by those whom we 

 nnist consider as his fellow-countrymen (though he was an 

 Englishman by birth) as most important and valuable, and 

 his name is not honoured in America only, but throughout 

 the world. 



John William Draper was born at St. Helen's, near 

 Liverpool, in 1811, and educated there and at the London 

 University (to which he was sent to study chemistry when 

 the University was first opened). He, left England soon 

 after for America, and completed his medical education :il 

 the University of Pennsylvania, graduating in 1836. He 

 was soon after appointed Professor of Chemistry in 

 Hampden Sydney College, Virginia, and in 1839 in the 

 University of New York. 



His earliest contributions to Science were on the 

 chemical action of light, on which he published nearly 

 forty memoirs. The following summary of his work on 

 this subject is fi-om a biographical sketch which appeared 

 in the Popidar Science Mouthhi, in January, 1874 (al)out 

 the time when I first made Dr. Draper's acquaintance). 

 I believe that though they may liave been editorially 

 revised by my esteemed friend Professor Youmaas, they 

 were in substance communicated by Dr. Draper himself, 

 thus possessing a special value at tht; present time, when 

 some of his most important researches are bearing fruit, 

 which others are claiming as their own : — 



"Of all the chemical actions of hght, by far the most 

 important is that of thc^ decomposition of carbonic acid by 

 the Ic-aves of plants, under the influence of sunshine. On 

 this the whole \«getable world depends for its growth, and 

 the whole animal world, directly or indirectly, for its food. 

 The decomposition in question is (;ssentially a deoxidation, 

 and up to about 1840 it was generally supposed to be due 

 to the violet rays of the sp(.'cti'uin, which, in accordance 

 with the views held at that time, were regarded as pro- 

 ducing deoxidising actions, and were consequently kno\\ n 

 as deoxidising ray.s. But this was altogether an assumj)- 

 tion unsupported by experimental proof. Professor Drapei' 

 .saw that thei-e was but one method for the ab.solute solution 

 of tlu! problem, and that was by causing the cUicompositi- 

 tion to take place in the spectnim itself. In this delicate 

 and beautiful experiment he succeeded, and found that the 

 decomposition was brought about by the yellow rays, at a 

 maximum by those in the vicinity of the Fraimhofer fixed 

 line D, and that the \ iolet rays might be considered as 

 altogether inoperative. The memoir containing this lesuit 

 was first read before the American Philosophical Societ}', 

 in Philadelphia, and immediately republished in London, 

 Paris, and Berlin. It excited general interest among 



