616 
NATURE 
[AuGUST 5, 1915 



frontal sinus, and a somewhat greater development 
of the forehead. This would indicate that the Boskop 
man was of the Neanderthal race, but more advanced 
in intelligence than the type specimen. 
The discovery of this skull offers an explanation of 
the origin of the Palaeolithic implements which are 
scattered in such vast profusion all over South Africa, 
and should it prove to be of the true Neanderthal race, 
as I have absolutely no doubt is the case, we then 
possess evidence that this remotely ancient type of man 
migrated into South Africa, and if we conclude the 
stone implements with which the country is strewn 
are his handiwork, then he must have existed here in 
large numbers. 
Mr. Piet Botha, the owner of the farm on which 
the>skull-cap was found, readily granted permission 
for me to excavate. I excavated the site of the find in 
person, and discovered portions of a rib and ,collar- 
bone, part of the mandible with a tooth in it; some 
more fragments of the skull, and a few roughly 
chipped stone implements. The remains were found 
at a depth of 6 ft. in alluvial gravel. On application, 
the South African Royal Society subsequently made 
a grant to this museum of tool. to carry on further 
excavations. The result was disappointing, a small 
portion of a human thigh-bone being the only result 
of this more extensive excavation. 
The skull-cap and other remains are now in the 
temporary possession of Dr Peringuéy, of the South 
African Museum, where a careful and detailed exam- 
ination is being made, but which cannot be completed 
until various data and measurements are procured 
from Europe. The first report will appear in the 
Journal of the South African Royal Society. 
F. W. Fitzsimons. 
Port Elizabeth Museum, Port Elizabeth, 

June 30. 
Mr. Firzsimons’s letter is the first authentic 
account published in Europe of the discovery of 
ancient human remains at Boskop Farm in_ the 
Transvaal. There can be no mistake about the im- 
portance of the discovery; the remains of Palzolithic 
man have at last been found in South Africa. As 
regards the nature or race of the _ individual 
thus found there is room for doubt; an exam- 
ination of the photographs of the skull-cap 
reveal none of the characteristic features of Neander- 
thal man; one can exclude that race with some degree 
of certainty. The individual to whom the skull-cap 
belonged was apparently of the modern type, with a 
head of remarkably large dimensions. European and 
American anthropologists look forward with great 
interest to the publication of a detailed account of the 
Boslkop discovery. ArtTHUR KEITH. 
Surface Tension and Ferment Action. 
THE correspondence in Nature of June 17 and July 
22 by Dr. Cramer and Drs. E. F. and H. E. Arm- 
strong on the possibility of the enzymic action of 
invertase being limited by surface tension, has led me 
to look up the laboratory records of some experiments 
which I made in 1892 on a cognate subject. I was 
at that time engaged in studying the formation of 
starch granules in various parts of the living plant, 
and the subsequent dissolution of the granules under 
the action of the cell enzymes. 
In the course of this inquiry I came across a curious 
fact which suggested that the action of the diastatic 
enzyme is to some extent dependent on physical con- 
ditions existing at the limiting surface of the starch 
granule and its surrounding medium. Briefly stated, 
this fact is as follows. 
NO. 2388, VOL. 95| 

If we mix with a dilute cold-water extract of malt 
a little solid starch of a kind which is readily attacked 
by diastase, e.g. that from buckwheat or barley, a 
microscopic examination will generally indicate a very 
appreciable erosion and partial disintegration of the 
granules within twenty-four hours, the actual time 
depending on the initial concentration of the enzyme. 
If a parallel experiment is so arranged that, with all 
other conditions remaining the same, the starch 
granules are kept im suspension by the addition of 
about 3 per cent. of gelatine, then we invariably find 
that the rate of erosion and dissolution of the starch 
is very much accelerated. This difference is also 
found to occur even if the mobile liquid which con- 
tains no gelatine is kept in continuous movement by 
mechanical means. 
It appeared to me that very possibly the lowering of 
the surface tension of the liquid by the gelatine had 
enabled the large-moleculed diastatic enzyme to pene- 
trate the granule with greater facility, and since the 
starch granules in plant-cells are suspended in highly 
colloidal protoplasm we might here have some sort of 
explanation of their rapid disappearance under the 
influence of very small amounts of active enzyme. 
Reasoning from these facts, I drew the conclusion 
that in a given mixture of starch and enzyme we 
ought to find a diminution in the rate of erosion in 
those parts of the liquid which are in a state of tensile 
stress. 
My first experiments in this direction were made in 
a flattened thermometer tube with an elliptical bore 
having a major axis of o-4 mm. and a minor axis of 
o-2 mm. The bore of the tube was charged with the 
diastatic liquid containing the starch-grains, which 
could be kept under microscopical observation through 
the walls of the tube. Under these conditions, the 
starch granules invariably showed a much higher 
resistance to erosion than did those of the same liquid 
contained in a small flask or beaker under similar 
conditions of temperature. At first sight this experi- 
ment gave some support to the idea of surface tension 
playing a part, but in a variation of it in which I used 
a thin film of the starch mixture between two inclined 
glass plates, I could find no difference in the rate of 
erosion in layers varying in thickness from 0-3 mm. 
downwards. 
[ then proceeded to investigate the action when 
the starch had been deposited in the interstices of 
porous substances, and in the first place used glass- 
wool, which was one of the substances employed by 
Messrs. Beard and Cramer, as described in their recent 
paper in the Proceedings of the Royal Society (vol. 
Ixxxviii., ser. B, p. 575), on surface tension and fer- 
ment action. Under these conditions the erosion even 
of buckwheat starch, which is the most sensitive to 
action of this kind, was entirely inhibited, no matter 
how long the reaction was allowed to continue. For 
a short time I was misled by this result, and it was 
only after I had recognised the distinct alkalinity of 
the solutions which had been in contact with the glass- 
wool that I found the causa causans was of a chem- 
ical and not of a physical nature. Diastase, like inver- 
tase, is extremely sensitive to traces of allxali, and 
can only exercise its maximum effect in a slightly acid 
medium. 
I satisfied myself that this was the true explanation 
by substituting for the glass-wool in the last experi- 
ment other porous substances, such as asbestos, cotton- 
wool, and filter paper. when the whole of the inhibitive 
effect disappeared. Thus failed my attempt to link 
enzymic action with surface tension, and even the 
original phenomenon with which I started, the apparent 
enhancing effect of a colloid like gelatine, admits of 
a different explanation based on the slightly acid 
reaction of the commercial product. It is now well 
