340 
in which an experiment on his own person was only 
prevented from proving fatal by timely swallowing of his 
shaving water, was a significant indication of the tho- 
roughyoing spirit in which all his researches were pur- 
sued. Asa pharmacien he rendered valuable service to 
the profession in connection with the last edition of the 
“Edinburgh Pharmacopceia,’’ merged since 1864, like 
those of London and Dublin, in the ‘‘Pharmacopceia 
Britannica,’ prepared under the auspices of the General 
Medical Council; and in his “‘ Dispensatory,’’ published 
in 1842 (second edition. 1848), he presented a commen- 
tary on the then existing Pharmacopceias, characterised, 
like his book on Poisons, by precision in details, and by 
the concise, yet happy expression of suggestive gene- 
ralisations. 
In the professorial chair Dr. Christison proved a singu- 
larly lucid and instructive lecturer. Himself strictly 
methodical in everything pertaining to scientific inquiry 
or professional routine, he fostered in his students habits 
of exact and well-regulated work. As the result of his 
incumbency, both the chairs he occupied gained no in- 
considerable accession of usefulness and importance ; 
while to that of Materia Medica he left a substantial 
legacy in the splendid museum, whose riches can never 
be appreciated till it is properly displayed in the new 
Medical School. By his students he was loved as well 
as admired; and once and again, in the course of his 
long career, old pupils scattered far and wide as busy 
practitioners, have shown themselves prompt to embrace 
every opportunity of doing him honour. 
As a member of the Senatus Academicus, and Assessor 
for that body in the University Court—an office to which 
he was elected five times in succession—Prof. Christison 
took an active and prominent part in the management of 
college affairs. No member of the University was more 
energetic in pushing forward that great scheme of exten- 
sion which, as now all but realised in a new Medical 
School, alongside of the new Infirmary, will doubtless 
raise Edinburgh to a yet higher position as a seat of 
medical education. The movement for better endow- 
ment of the University also found a warm supporter in 
one who was ever ready to advance what he believed to 
be the true interests of learning. An ardent lover of all 
manly exercises, the doctor was himself noted, in his 
youth, as the most accomplished athlete in the Uni- 
versity. A story is told of his having, on one occasion, 
accomplished the rarely equalled feat of running from the 
College gate to the top of Arthur seat within twenty-five 
minutes. In after years, athleticism would often form 
part of the diversions with which the Professor and his 
friends relieved the cares of professional life. Even as 
an octogenarian the vivacious Professor continued to 
be remarked for the almost jaunty elasticity of his 
step. 
by the Edinburgh Medical Faculty his eminence was 
duly recognised in his election on two distinct occasions 
—in 1838, and again in 1846—to the presidentship of the 
Royal College of Physicians, an honour which was fitly 
followed up by the Fellows according a place in their hall 
to his portrait by Sir John Watson Gordon. On the 
death of Sir David Brewster, he was elected president of 
the Edinburgh Royal Society ; and in this office, held 
from 1868 to 1873, as well as in the vice-presidentship, 
which he had formerly filled, he acquitted himself with a 
distinction which the Society acknowledged by adding 
his portrait to their gallery of illustrious men. Assiduous 
in his attendance at the Society’s meetings, Dr. Christison 
from time to time contributed papers to the 7vansactions. 
Among the subjects thus discussed may be mentioned 
that ot fossil plants in the coal formation, and the remains 
of ancient trees found in Craigleith and other quarries, 
on the study of which he brought to bear the resources of 
chemical analysis. In 1857 Dr. Christison’s position 
among Scotch physicians was fitly recognised in his being 
NATURE 
[ Feb. 9, 1882 
nominated by the Crown to represent the profession in _ 
Scotland at the General Medical Council. After having 
for many years held the honorary office of a Physician in 
Ordinary to the Queen for Scotland, Prof. Christison in 
1871 was created a baronet of the United Kingdom, a 
distinction which was conferred on the recommendation of 
the then Prime Minister, Mr. Gladstone. In 1873 he 
celebrated the jubilee of his professorship, an occasion of 
which friends and admirers were eager to take advantage 
for testifying their appreciation of the veteran physician. 
In 1875 he presided over the Edinburgh meeting of the 
British Medical Association. The veteran's general 
standing as a scientific man was no less unmistakably 
certified in his being selected, in 1876, for the president- 
ship of the British Association for the Advancement of 
Science: though this honour, in deference to the advice 
of friends, who feared the effort might overtax his 
strength, he felt constrained to decline. It was not many 
months later that an illness, by which he was for a time 
completely prostrated, led to his resignation of professorial 
duty. 
Sir Robert Christison was married in 1827 to Henrietta 
Sophia, daughter or Mr. David Brown, of Greenknowe, 
Stirlingshire. Mrs. Christison died in 1849; but there 
survive three sons, of whom Alexander, the eldest, born 
in 1828, was educated at the Edinburgh Academy and 
High School, and after serving in various capacities, is 
now Deputy Surgeon-General of the Bengal Army. 
CONCERNING THE GAS-FLAME, ELECTRIC, 
AND SOLAR SPECTRA, AND THEIR 
EFFECTS ON THE EVE 
¢ Pek spectra of the light from these various sources is 
a subject to which I gave some attention about two 
years ago, and a detailed account of my experiments 
may be found in the Proceedings of the American Aca- 
demy of Sciences for 1880, p. 236. In this article it was 
shown that the colour of the sun was not what the aver- 
age person would call white, but decidedly bluish. The 
sun’s ‘‘golden glare’? spoken of by Mr. Capron is en- 
tirely a subjective effect (except when near the horizon) ; 
and follows from the well-known Jaw that bright lights 
tend to look yellow, and faint ones blue. If the highly 
magnified images of two diaphragms egva//y illuminated, 
one by the electric light and one by the sun, be cast upon 
a screen, the distinctly bluish character of the latter will 
be strongly marked. Indeed, the magnesium light is more 
blue than the electric, and hence probably is of a higher 
temperature, although being spread through a larger 
space, has less available heating power. As far as mere 
colour is concerned then, the electric light approaches 
nearer to the sun than does the gas-flame. 
From subsequent experiments, however, it is my im- 
pression that colour has nothing whatever to do with the 
painful effects sometimes noticed in the eyes, after long 
and continuous work by artificial light. To test this 
question, I had a tin lamp-shade constructed, consisting 
of atube six inches in diameter by eight in length. One 
end was closed by a reflector, and the other by a piece of 
very light blue glass. Two holes were made in the sides, 
through which passed the glass chimney of an Argand 
gas-burner. By experimenting with a shadow photometer, 
a position was found where the light received on a book 
was of the same intensity, and very similar colour, to 
that from a window in the daytime, at a distance of about 
six feet. A few minutes’ reading, however, was sufficient 
to convince me that the new light was far more trying to 
the eyes than an ordinary gas-flame would be. The ill- 
effects being due to the intense heat thrown down by the 
reflector. And this I think is the source of the whole 
trouble in the ordinary gas-burner. The heat radiated by 
the flame, the heated chimney and shade, and reflected 
