90 NATURE 
[Marcu 25, 1915 

Several species of American marsupials are figured 
by seventeenth-century writers, such as J. E. Nierem- 
berg (1635), George Marcgrav (1648), César de Roche- 
fort (1658), and others. An illustration given by the 
last-named author is here reproduced (Fig. 1). 
C. R. EastMan. 
American Museum of Natural History. 

Differential Antiseptic Action of Organic Dyes. 
AN important property of certain organic dyes is 
their differential antiseptic action. Thus, varieties of 
B. coli commonly met with in the intestine are more 
susceptible to the inhibitory action of the tetraethyl- 
diamidotriphenylmethane derivative, ‘brilliant green,” 
than are typhoid or paratyphoid bacilli. The use of a 
fluid culture medium containing this dye (along with 
telluric acid) facilitates greatly the isolation of scanty 
typhoid and paratyphoid bacilli from faeces, since the 
growth of the various members of the coli group can 
be restrained, while the organisms in question pro- 
liferate actively. The detection of cases of typhoid 
infection, e.g. in ‘‘carriers,’’ which is frequently a 
difficult bacteriological problem, can be materially 
simplified by this procedure. But our supplies of 
brilliant green have hitherto been derived from Ger- 
many, and I shall be indebted to your readers for 
information as to whether this dye is prepared in a 
fairly pure state by anyone in this country. 
H. BRowniInc. 
The Bland-Sutton Institute of Pathology, 
The Middlesex Hospital, London, W. 

The Physical Properties of Isotopes. 
Dr. LINDEMANN (Nature, March 4) deduces that the 
vapour pressure of lead from, radio-active origin, or 
of radium D, should be very considerably different 
from ordinary lead at comparatively low temperatures. 
It would be no easy matter to test this at such a low 
temperature as 100° C. However, it is being found 
possible to make measurements of the vapour pressure 
of cadmium down to 10-® mm., and the method 
should be applicable to the point in question. 
It is interesting to note in connection with the last 
paragraph of Dr. Lindemann’s letter that the arc 
spectra of lead of radio-active origin and of ordinary 
lead. show no difference, as Mr. T. R. Merton has 
recently found, further confirming the view. that the 
external electrons are responsible both for the spectra 
and the individual chemical properties of elements. 
ALFRED C. EGERTON. 
1g Old Court Mansions, Kensington. 

A Misprint in Halphen’s ‘‘ Fonctions Elliptiques.”’ 
Havinc recently had to use Halphen’s multiplica- 
tion formula for the special cases of the lemniscate 
functions (g,=o), I have convinced myself that there 
is a rather serious misprint in his expression for Wy 
(vol. i., p. 96), namely, instead of + 5.¢3 in the last 
term, we should read —34.¢3. Thus with g,=4, and 
this correction, we have 
¥i= 0" —2¢°+ 1094+ 109? 2) 
= —20(@' +1) (94-69?+1) 
where the factor (@?+1) can be foreseen from the 
theory. With the other sign we have no such resolu- 
tion. G. B. Matuews. 

Early References to ‘Musical Sands. 
AN allusion to musical sands may be found in one 
of the tales from the ‘‘ Arabian Nights "—‘ The Story 
of the Two Sisters who were jealous of their Younger 
NO. 2369, VOL. 95] 


Sister." Prince Bahman, who was journeying in 
search of rarities and treasures, reaches the foot of 
a mountain, and while ascending ‘‘ was assailed with 
the most hideous sounds,’’ while others who followed 
him heard ‘‘ groans, shouts, and all sorts of insulting 
epithets.” One of the wonders they were in search 
of was the “Singing Tree,” which ‘‘commenced to 
issue a series of exquisite strains of music”’ as soon 
as the Princess Parizadé saw it. 
Ceci, Carus-WILson. 
March 21. 

TWO CHINESE TOURS.1 
SOMEWHAT unexpected sequel to the 
mission which Sir Francis Younghusband 
led to Lhassa in 1903-4 was the appreciation by 
Chinese officials of the fact that the trade in 
Indian opium, which has at times been held up 
as a reproach to England, was in reality due to 
the demand of China for the drug. It is interest- 
ing to reflect that the truth should first have 
dawned upon a Chinese envoy who had been edu- 
cated in the United States. The novel idea took 
root and engendered a movement which spread 
in China with such rapidity that in 1906 an 
imperial edict dealing with the opium question 
was promulgated. This rescript embodied 
elaborate provisions for the immediate curtail- 
ment and the gradual extinction of the use of the 
drug. Necessarily, therefore, it took account 
not only of the enormous Chinese out-turn of 
opium, but of the smaller, though still important 
amount imported from India. Proposals and 
counter-proposals were accordingly formulated in 
1907 by the Governments of China and Britain, 
and certain regulations, to remain effective for 
three years, were agreed upon by the high con- 
tracting parties and became operative in 1908. 
Meanwhile the Government of the United 
States thought fit to initiate a movement of an 
international character which culminated in the 
assembly at Shanghai in 1908 of an opium com- 
mission, the findings of which reflect a desire to 
aid the Chinese authorities in their crusade 
against the opium habit; while, before the pre- 
liminary period of three years had expired, 
negotiations for a new agreement between China 
and the United Kingdom were set on foot. As 
a preliminary to the ratification of this agree- 
ment it was desirable that his Majesty’s Govern- 
ment should know what had been the actual 
effect in China of the restrictive measures adopted 
there in response to the imperial injunctions ot 
1906. The officer to whom the important duty 
of reporting upon this feature of the case was 
Sir Alexander Hosie. No one better fitted for 
the duty of traversing the six provinces of China, 
known to have been the chief opium-producing 
areas in that empire, could have been selected. 
Sir Alexander had already travelled extensively, 
and in some cases, as an officer of the Chinese 
Consular Service, had resided in the provinces 
1 “On the Trail of the Opium Poppy. A Narrative of Travel in the Chief 
Opium-producing Provinces of China.” By Sir Alexander Hosie. 2 vols. 
Vol. i., pp. vilit+3co. Vol. ii., pp. 308. (London: G. Philip and Son, Ltd., 
1914.) Price 25s. net 2 volumes. 
