J.— PSYCHOLOGY. 181 



Hospital, laying special stress on their psychological aspect. About 

 the same time, at the request of Professor Sully, he began to lecture on 

 experimental psychology at University College, London. 



Meanwhile, at Cambridge Michael Foster was seeking someone who 

 would give instruction there in the physiology of the sense organs, 

 McKendrick having, as Examiner in Physiology, recently complained of 

 the inadequate training of the Cambridge students in this branch of the 

 subject. Foster's choice fell on Elvers, and in 1893 he invited him to 

 the University for this purpose. For a few months Elvers taught 

 simultaneously at Cambridge and at Guy's Hospital and at University 

 College, London. He went to Germany for a short period of study 

 under Professor Krapelin, then of Heidelberg, whose brilliant analysis 

 of the work curve and careful investigations into the effects of drugs 

 on bodily and mental work had aroused his intense interest. In colla- 

 boration with Krapelin he carried out a brief investigation into mental 

 fatigue and recovery, published in 1896 (Journal of Mental Science, 

 vol. xlii., pp. 525-29, and Krapelin's Psychologische Arbeiten, vol. i., 

 pp. 627-78), which indicated that even an hour's rest is inadequate to 

 neutralise the fatigue of half-an-hour's mental work, and paved the 

 way for Eivers's important researches some ten years later upon the 

 effects of drugs on muscular and mental fatigue. 



At Cambridge Elvers set himself to plan one of the earliest systematic 

 practical courses in experimental psychology in the world, certainly the 

 first in this country. In 1897 he was officially recognised by the 

 University, being elected to the nevv^ly established Lectureship in Physio- 

 logical and Experimental Psychology. But the welcome and encourage- 

 ment he received from cognate branches of study at Cambridge could 

 hardly be called embarrassing. Even to-day practical work is not 

 deemed essential for Cambridge honours candidates in elementary 

 psychology; psychology is not admitted among the subjects of the 

 Natural Sciences Tripos ; and no provision is made for teaching the 

 subject at Cambridge to medical students. Elvers first turned his 

 attention principally to the study of colour vision and visual space per- 

 ception. Between 1893 and 1901 he published experimental papers 

 ' On Binocular Colour-mixture ' (Proc. Cambs. Philosoph. Soc, 

 vol. viii., pp. 273-77), on ' The Photometry of Coloured Papers ' 

 (J. of Physiol., vol. xxh., pp. 137-45), and ' On Erythropsia ' (Trans. 

 Ophthal. Soc, London, vol. xxi., pp. 296-305), and until 1908 he was 

 immersed in the task of mastering the entire literature of past experi- 

 mental work on vision, the outcome of which was published in 1900 

 as an article in the second vohune of the im])ortant ' Text -book of 

 Physiology ' edited by Sir Edward Sharpey Schafer. 



This exhaustive article of 123 pages on ' Vision ' by Elvers is still 

 regarded as the most accurate and careful account of the whole subject 

 in the English language. It is of special value not only as an encyclo- 

 pfedic storehouse of references tO' the work O'f jirevious investigators — 

 although with characteristic modesty Elvers omits to mention himself 

 among them — but also for the unsurpassed critical account of the prin- 

 cipal theories of colour vision. In it he displayed the strength and the 

 weakness of Ilering's theory and the untenability of Helmholtz's 



