eo ee OE 
| ids 


r 
FEBRUARY 17, 1923] 
. 
NATURE 235 

ished in connexion with this disease is that its spread 
coincides with efforts to get more latex from the trees. 
Sharples chronicles briefly the progress of investiga- 
tions promoted by a representative Brown Bast 
Investigation committee formed in Malaya in 1918, 
but owing to changes of personnel this committee 
appears to have ceased to function in 1920 although 
_ investigations still proceeded. He also passes in 
critical review a number of papers recently published 
on the subject which were also noticed in NATURE 
for March 16, 1922 (vol. 109, p. 357). One general 
result of the investigations under the auspices of 
the committee is to strengthen the conclusion, also 
reached by Rands in Java, that while various 
organisms may be casually connected with the 
disease, none can be considered causal and the disease 
must apparently be definitely added to the list of 
pathological physiological conditions of obscure 
origin. In view of confident assertions by Keu- 
chenius in Sumatra that bacterial inoculations 
produced a similar disease, this conclusion was very 
critically re-examined and comparative inoculations 
made with the organism used in Sumatra; the 
evidence against bacterial causation thus accumulated 
is very convincing. On the other hand, the Malayan 
experiments supply further experimental evidence 
that increased tapping of the latex, either by more 
_ frequent incision or by a wider cut, greatly increases 
the percentage of trees attacked by brown bast. 
Sharples reviews recent suggestions that various 
anatomical peculiarities may throw light upon the 
pathology of the disease. He regards the pockets 
of laticiferous tissues enclosed within wound cork, 
recorded by Sanderson and Sutcliffe, as after-effects 
of little value in elucidating the causes of the disease, 
and he points out that lignification and necrosis 
of sieve-tubes, such as is recorded by Farmer and 
Horne, may frequently be seen in perfectly healthy 
plants. 
RAINFALL IN 1922.—The British Rainfall Organiza- 
tion, which now forms a part of the Meteorological 
Office, Air Ministry, has made a hurried scrutiny of 
the rainfall records for 1922 in time for insertion 
in the Meteorological Magazine for January, which 
is published in the middle of the month. Several 
thousand returns are said to have been already 
received and a selection has been made of those for 
which average returns exist; 280 such records have 
been examined and they afford sufficient data for 
the construction of a rainfall map. The rainfall for 
the individual months shows that the rain over the 
country as a whole was close to or above the average 
except in the autumn. The total was excessive over 
England in July, yielding locally more than double 
the average. October was exceptionally dry, the 
rainfall being in England and Wales 33 per cent. 
of the normal, in Scotland 59, and in Ireland 37 per 
cent. In England and Wales the only months with 
a deficiency of rain were May, June, October, and 
November. In Scotland there were six months with 
an excess and six months with a deficiency, the 
first seven months being wet with the exception of 
March. In Ireland there were only five months with 
a deficiency of rain; these were March, May, June, 
October, and November. The country as a whole 
had practically the normal fall for the year. The 
Times for January 29 had a detailed article on the 
rainfall of the past year, in agreement with its 
practice followed for many years past. It shows 
that 1922 was almost entirely devoid of remarkable 
features. Among the selection of records available 
the variations of rainfall registered in 1922 ranged 
from 115-25 in. at Seathwaite to 18-66 in. at Shoebury- 
ness. The map giving the rainfall over the British 
NO. 2781, VOL. 111 | 
“Isles shows that there was a general deficiency of 
rain in Scotland and Ireland and a general excess 
‘over England, although in the extreme south-east, 
where the drought of 1921 reached its climax, the 
rainfall of 1922 was again below the average; but 
the deficiency apparently nowhere exceeded 10 per 
cent. The date given at head of Table II. for all 
columns except the average should be 1922 and not 
1921. 
REcENT Votcanic Activity In S. AFRiIca,—Dr, 
P. A. Wagner has written a very thorough and 
interesting memoir on ‘‘ The Pretoria Salt-pan, a 
soda caldera,” for the Geological Survey of S. Africa 
(Mem. No. 20, 1922, price 7s. 6d.). A saline lake 
some 25 miles north-west of Pretoria has long been 
used by natives as a source of common salt, and in 
recent’ years it has been worked on a commercial 
scale on account of the sodium carbonate in its 
waters. Excellent photographs are given of this 
zoutpan in its primitive and its industrialised con- 
ditions; but the most interesting of the numerous 
illustrations are those showing the form and the 
walls of the depression in which it lies. The author 
proves clearly that we are here dealing with a true 
caldera of explosion. If at any time a layer of 
volcanic scoria covered the broad cone of eruption, 
all traces have disappeared through denudation. It 
is far more probable that the walls were built up 
entirely of fragments exploded from the granite and 
dolomite that underlie the area. Their structure is 
seen in a number of cliff-sections, and the freshness 
of the whole ring suggests a Quaternary age for the 
paroxysm that actually domed up the granite cover 
and flung the fragments for 1700 feet on all sides 
from the central pipe. The perimeter of the caldera 
measures 11,100 feet. The saline layers from which 
the soda is mainly derived are a trona bed above 
and a bed of the rarer carbonate, gaylussite, in the 
muds below. There is a remarkable absence of 
sodium sulphate. Dr. Wagner gives good reasons 
for regarding the salts as of magmatic origin. Now 
that a kimberlite pipe in the Cape Province has been 
proved to be of post-Neocomian age (see NATURE, 
vol. 110, August 19, 1922, p. 262), evidence of volcanic 
outbreaks linking the southern region with the still 
active areas near the great lakes will be sought for 
with a lively interest. Folding sections and a map 
on a large scale accompany this comprehensive 
memoir. 
PALHOBOTANY AND THE GONDWANA CONTINENT.— 
Recent contributions to palaobotany will be found 
in the Quarterly Journal of the Geological Society, 
vol. 78, Part 3, where Prof. A. C. Seward describes 
carboniferous plants from Peru (pp. 278-83), and 
Seward and R. E. Holttum report upon Jurassic 
plants from Ceylon (pp. 271-77) ; and in the Geological 
Magazine (vol. 59, pp. 385-92, September 1922) Prof. 
Seward has a note upon fossil plants from the 
Tanganyika Territory. Dr. A. B. Walkom (Queens- 
land Geological Survey Publication, No. 270) has 
recently commenced the publication of a monograph 
upon the Paleozoic Flora of Queensland, while the 
general issues and problems of distribution and of 
plant migration across regions of the globe that at 
the present day provide impassable oceanic or 
climatic barriers is raised by Prof. Seward in the 
Hooker lecture published in the Linnean Society’s 
Journal for October 1922. These new palewobotanical 
data recorded above supply more facts for land areas 
that presumably were organically linked in Mesozoic 
times through the great Gondwana continent of 
which India now remains one of our most authentic 
relics. It is therefore interesting to note, from the 
