54 



NATURE 



[March 20, 19 13 



to the centre. Vet there is a colour-blindness of 

 the normal peripheral field which is analogous to, 

 though possibly not identical with, congenital 

 colour-blindness. One of the assumptions, how- 

 ever, which is made, in the endeavour to make the 

 theory suit the case of colour-blindness, is that 

 the colour-blind "white" is altogether different 

 from the normal-eyed "white." According to Sir 

 William Abney, the "white" of the "red-blind" 

 is a sea-green, and that of the "green-blind " a 

 brilliant purple. But it would appear from the 

 nature of the actual experiments on which this 

 assumption is based (pp. 273, 274) that there is 

 here only a confusion between the sensations to 

 which these colours give rise in normal eyes and 

 the neutral sensations which thev evoke in the 

 colour-blind. 



In every case of complete colour-blindness 

 (which causes colour-confusion only and is distin- 

 guished, therefore, from total loss of any colour 

 perception) there are two hues which, though most 

 definite and vivid to the normal-eyed, appear alto- 

 gether uncoloured or neutral. Only one of these 

 neutrals is to be found in the spectrum, though 

 both can be produced by combinations of spectral 

 colours. This is obviously something different 

 from a demonstration of the manner in which what 

 to the normal eye is white is seen by the colour- 

 blind. But it may be asked : Is there any reason 

 for entirely giving up the trichromatic theory 

 because it does not meet with general acceptance 

 when " doctored " to suit the case of colour- 

 blindness? A study of Sir William Abney 's work 

 must convince one how strongly it is supported 

 by physical facts. 



A quotation from the preface may fittingly con- 

 clude a necessarily too short notice of this valu- 

 able and comprehensive work. The author there 

 makes the following suggestive remark : — 



"A theory, to be one of perfection, must offer 

 the truth, the whole truth, and nothing but the 

 truth. The trichromatic theory offers the truth ; 

 but the physiologists must add their quota to 

 make it the whole truth. There may be difficulties 

 in welding together the physical and physiological 

 aspects of colour vision to make a perfect theorv, 

 but it will be effected." 



A MEDIEVAL PHYSIC I AX. 

 John of Gaddesden and. the Rosa Medicinae. By 

 H. P. Cholmeley. Pp. 184. (Oxford: Claren- 

 don Press, 1912.) Price 85. 6d. net. 



OLD books, at any rate old medical books, 

 may, as regards their contents, be divided 

 into three classes: those intrinsically valuable as 

 sources of more or less original knowledge — of 

 such are the Hippocratic writings, Galen, Alex- 

 NO. 2264, VOL. 91] 



ander of Tralles, some of the Salernitan treatises, 

 the greater medieval Italian and French surgeons, 

 Sydenham, Morgagni — names taken at hazard ; 

 secondly, those which, although not original 

 sources, yet enshrine more or less admirably the 

 works of great men or of schools which had other- 

 wise perished — of such are Celsus, our chief re- 

 source for the doctrines of Alexandrian medicine, 

 or Caelius Aurelianus, which preserves for us some 

 of the writings of Soranus, or Aretaeus, or 

 Oribasius — names again chosen at random, or 

 smaller books which also, as rafts or broken 

 pieces of the ship, may salve lesser fragments 

 of ancient lore — books such as Aetius or Paul 

 of ^T£gina ; and, thirdly, old books which have no 

 other value than the bibliophile may, in the fashion 

 of the time, choose to confer upon them as 

 antiques. These books, for their quaintness, may 

 arouse some interest, and of such is the book 

 before us. 



John of Gaddesden's book may in its time have 

 served as a handy " Practica " for his contem- 

 poraries, but in later centuries probably the best 

 use it has served is as a nucleus around which Dr. 

 Cholmeley has gathered much interesting historical 

 matter, very aptly and pleasantly put together. 

 The original John is poor stuff. His editor 

 respectfully offers to him some tribute, asking 

 us to recognise at least his clinical insight. John, 

 who died in 1 361, highly educated at Oxford and 

 in later life a fashionable Court physician, enjoyed 

 great advantages of experience, and no doubt 

 brought these advantages to the construing of 

 his Oxford "Theoretica" and "Practica"; but 

 his own contributions were exiguous. Arderne, if 

 no great author, was at any rate superior to John 

 of Gaddesden, and we hope that the success of this 

 edition may tempt Dr. Cholmeley to follow up Mr. 

 D'Arcy Power's pioneer work with a like volume 

 on Arderne. 



In studying the writings of early physicians we 

 must continually remember that literary ethics was 

 not born until modern times — almost in our own 

 day. It is scarcely fair to these old men, when 

 they lifted pages upon pages from their fore- 

 runners, to accuse them of "shameful plagiary." 

 They all did it, and not in medicine only; and not 

 only the inferior authors, but the most reverend 

 of them also. So John, with a pious obsequious- 

 ness, helped himself to what he could find else- 

 where to serve his purpose. As a specimen of 

 John's wonderfully vivid clinical pictures, Dr. 

 Cholmeley quotes his description of obstructive 

 jaundice with ascites. It is vivid, no doubt ; but 

 we may be sure that it is not John's. To track 

 out the sources of all or many of his purple 

 patches would be a long business, but in respect 



