464. 
NATURE 
further observation, and will at last enable us to arrive 
at the antiquity of man within certain probable limits of 
error. Without laying stress on any portion of the above 
very rude estimate, it may, I think, be averred that it is 
not palpably too high, but is just as likely to be too low ; 
and this last supposition will be rendered more probable 
when we consider the vast lapse of time implied by the 
position of some of the recently discoverd palzeolithic 
weapons. 
The flint tools found in the gravel at Bournemouth, in 
the Isle of Wight, and near Salisbury, at elevations of 
from 80 to 100 feet above the present valleys, imply, ac- 
cording to the best observers, that the whole series of sur- 
rounding river valleys have been excavated since they 
were deposited, and that the system of drainage and posi- 
tion of the coast-line have been very greatly altered. The 
hippopotamus of the Gower Caves implies changes equally 
great, since the peninsula of Gower now contains only 
small streams, and could not possibly have had a large 
river without very important changes in its relations to 
the adjacent country. The position of the flint weapons 
in the valley of the Somme, at Hoxne in Suffolk, and in 
many other places, all combine in indicating that very 
important changes in physical geography have taken 
place since they were deposited. We can hardly 
suppose that in all these different localities the changes 
were abnormally rapid, especially as in no case 
do records of the historic period indicate that any 
remnant of the process was then going on; and from 
what we do know of the rate of such changes, and their 
intermittent nature, we are entitled to affirm that the most 
extreme estimates yet made of the antiquity of the men 
who fashioned and used the palzolithic implements is 
quite as likely to be under as over the truth, 
There is as yet no clear evidence that man lived in 
Northern Europe before the glacial epoch, and even if he 
did so the action of the ice sheet would probably have ob- 
literated all records of his existence. Every evolutionist, 
however, now believes that he must have existed far back 
in the tertiary period, and that the proof of it will be 
found, if at all, in some of the warmer regions of the old 
world. Here is surely a problem of grand and absorbing 
interest awaiting solution at our hands. Geologists are 
not usually wanting in energy or enterprise, and they 
number in their ranks many wealthy men. It is to be 
hoped that they will soon energetically attack the prob- 
lem ; and no more promising field of research offers itself 
than the limestone caves of Borneo, which can be explored 
with perfect safety, and at a moderate expense.- We can 
hardly now expect any great additions to our knowledge 
respecting the antiquity of man in Northern and Central 
Europe, and must go to warmer regions if we wish for 
new discoveries and startling revelations. 
A. R. WALLACE 
LETTERS TO THE EDITOR 
[Zhe Editor does not hold himself responsible for opinions expressed 
by his correspondents. No notice is taken of anonymens 
communications. | 
Fellowship at Magdalen College 
I THINK the noticejin NATURE of Sept. 25 respecting the 
election about to take place to a Natural Science Fellowship at 
Magdalen College requires some comment. The amount of 
academic preferment which falls to the share of science in Oxford 
is so small, that it might reasonably be demanded that what 
there is should be thrown open to as many candidates as possible, 
When, therefore, it was announced that the Fellowship would 
be given for proficiency im Biology, it might have been inferred 
that the electors had this object in view. Biology is held, else- 
where than in Oxford, to be the science which treats of the laws 
governing organization and vital activity ; in other words, struc- 
ture and function in a// forms of life, whether vegetable or animal, 
It was not, perhaps, an unreasonable inference, therefore, to 
draw from the terms of the notice, that it was the intention of 
the College to make Biology in its widest sense the foundation 
of the examination, and to allow individual candidates to exhibit, 
in addition, such detailed knowledge as they might possess of 
Zoology, Botany, or even Paleontology. This would not have 
attributed to Biology a wider meaning than, for example, Mr. 
Herbert Spencer or the Science and Art Department attach to 
it. Thinking it desirable, however, to get some official in- 
formation upon the subject, I wrote to the President, who, after 
some delay, replied that, in his opinion, as preference would be 
given to Biology, it would be useless to offer Botany as a special 
subject. This is not more reasonable than it would be to say, 
that because Physics was to be the subject of an examination it 
would be useless to offer Electricity or Heat as a special subject. 
But the terms of the President's reply were rather ambiguous, and 
I therefore made some further inquiries. I learnt, as the result, 
that the College considered it impossible to compare the merits 
of a candidate who stood on the Zoological, with one who stood 
on the Botanical, side of the general subject . : 
I think myself the difheulty is not one which should have been 
found insuperable ; but, assuming that the College had sufficient 
grounds for a different opinion, then I think the electors should 
not have offered their Fellowship for Biology, when what they 
really had in view appears to be a detailed knowledge of the 
Zoological preparations in the University Museum, 
W. T. THISELTON DYER 
The Sphygmograph 
THERE appears in NATURE, vol. viii. p. 330, a notice of a 
thesis for the M.D. Cantab. on the subject of Bright’s disease, in 
which reference is especially made to some sphygmographic 
observations therein contained. It is apparently from the pen of 
Mr. Garrod, who is himself the author of interesting aiid im- 
portant researches with the sphygmograph and cardiograph. 
While agreeing with a part of my explanation of the normal 
pulse tracing, as regards the points in which it differs from the 
view commonly received, he takes exception to the account 
which I have given of the tidal or first secondary wave. It may 
be well to say in reply a few words upon the point at issue, 
since the reference to it in the thesis was very brief and inci- 
dental, and I should not wish it to be taken as a full account of 
my views as to the mechanism of the pulse. 
The explanation of Mr, Garrod himself is that the tidal wave 
is an instantaneous wave due to the closure of the aortic valves, 
This theory was first proposed by M. Marey to account for the 
tidal wave in many of its forms ; but, so far as I know, it has 
not been adopted by any writer on the subject in England with 
the exception of Mr, Garrod. There is this difference, however, 
between them, that while M. Marey holds that the dicrotic wave 
has nothing to do with the aortic valves, but is a reflection from 
the periphery, Mr. Garrod considers that it is the wave of ex 
pansion from the closure of the aortic valves, which becomes 
separated from the instantaneous wave as it recedes from the 
heart. Thus the faculty of originating two waves of different 
velocity, which by most writers is attributed to the first impulse 
of the heart, combined with the closure of the mitral valve, is 
es Mr. Garrod denied to that event, but ascribed to the closure 
of the aortic valves. Now I believe it to be mechanically im- 
possible for any wave to be propagated with a velocity different 
from that of the wave of expansion, except the purely vibtatory 
wave of sound, and Mr. Garrod appears himself to hold that & 
mere vibration produces no elevation in the tracing, The ques 
tion, however, may easily be determined experimentally. t 
there appear in the tracing two waves which are travelling with 
different velocities, their relative position will vary at different 
distances from the heart. Let, therefore, anyone who wishes 
toysettle the question for himself take tracings of a good many 
