422 
NATURE 
[Marcu 31, 1923 

quantitative tests for sugar in the blood. It is probable 
that many a preparation of pancreas has failed, in the 
past, to become established because its physiological 
activity could not be satisfactorily tested and recourse 
was limited to casual clinical trials. When one con- 
siders the plethora of commercial pancreatic prepara- 
tions already on the market, which claim to contain 
the specific sugar-destroying principle, it is comforting 
to know that the Medical Research Council has taken 
the action it has, and that its own experts are 
actively engaged in studying methods that may yield 
preparations of uniform potency. In connexion with 
these difficulties, we note with some interest Dudley’s 
work at the National Institute in refining pituitary 
extract. Apparently, the further the purification 
was carried, the less potent the substance became 
physiologically. This is not the first time that such 
stumbling-blocks have interfered with attempts to 
refine biologically potent principles contained in organ 
extracts or in culture fluids which have served for the 
growth of micro-organisms. 
It would be superfluous to attempt to enumerate 
the many lines along which research is being pursued, 
either by expert workers at the National Institute or 
by the many outside specialists whose work the Medical 
Research Council encourages or finances ; nor can we 
mention even the terms of reference of the numerous 
committees and sub-committees which have taken 
upon themselves the task of co-ordinating attack 
upon a multitude of problems in all fields of scientific 
medicine and hygiene. Membership of these com- 
mittees is no sinecure, and it is notorious that much 
self-denying work is performed. Verily, the appre- 
ciative tax-payer can have no reason to grumble 
at the way in which his exiguous contribution to the 
community’s health is expended. 
Now what has the report to say to the watchman 
seeking for a sign? We believe the organisation of 
research under the xgis of a responsible body of 
scientific advisors is a valuable national asset. Will 
such organisation interfere with the individual freedom 
of the research worker? Is there a danger that the 
extension of the team-principle and the laying down 
by a higher authority of precise research programmes 
may stifle what originality the worker may possess ? 
The answer is, we believe, that there are men who 
work best in a team and men who prefer to work alone, 
and that there is ample room for both types. There 
are periods both in war and in peace when stocktaking 
of knowledge is essential if we are again to make 
advance into the unknown. The present is one of 
those times of national stocktaking in medical science. 
The very fundamentals of many departments of medical 
science require revision. A doyen of the chemical 
NO. 2787, VOL. 111] 

world recently referred to certain developments and 
proposals in biological chemistry as being simply 
re-search, with the accent and insistence on the first 
syllable. 
The statement is both true and false. Simple 
reconstruction must inevitably form an integral part 
of modern research. Possibly the biological sciences, 
on which advance in scientific medicine mainly hangs, 
contain a greater proportion of inexact, un-coordinated, 
and incomplete statement than the so-called exact 
physical sciences. Every advance in the latter reacts 
on biology, necessitating re-search in some form or 
other. Co-ordinated investigation by teams is neces- 
sary In peace as in war, and the fruit will duly appear. 
The scientific investigation of deficiency diseases—a 
war-time necessity—has developed into something 
like a science of its own. The organised investigations 
on anerobic bacterla—another war-time necessity— 
which was perhaps a very typical example of a 
re-search, has already borne abundant fruit in recent 
exact studies of such diseases as botulism and braxy. 
What of the night? The morning cometh. 
j-GeGaie 

The Fourier-Bessel Function. 
(1) A Treatise on Bessel Functions and their Applica- 
tions to Physics. By Prof. A. Gray and G. B. 
Mathews. Second edition prepared by A. Gray and 
Dr, T. M. MacRobert. Pp. xiv+327. (London: 
Macmillan and Co., Ltd., 1922.) 36s. net. 
(2) A Treatise on the Theory of Bessel Functions. By 
Prof. G. N. Watson. Pp. viii+804. (Cambridge: 
At the University Press, 1922.) os. net. 
HE function to which these volumes are devoted 
received its name from the astronomer Bessel, 
1824, on introducing it for the coefficients in the ex- 
pansion of radius vector, and true or eccentric anomaly 
in a Fourier series of sines and cosines of multiples of 
mean anomaly or time. Two years before, in 1822, 
Fourier had encountered the same function essentially 
in his analytical theory of heat, and his variable is the 
square of the variable of Bessel. 
The function is, however, first met in a dynamical 
problem, of the oscillation of a vertical chain, investi- 
gated by Bernoulli, 1738, and here the Fourier form is 
the natural one to use. The oscillation is replaced by 
a steady motion of permanent shape in a chain hanging 
down, and revolving bodily, and this is easy to realise 
experimentally ; the plane oscillation is then seen in 
the shadow on a vertical wall. 
Take the condition of relative equilibrium of a length 
x above the lowest point, where it is assumed that the — 
displacement is small enough for vertical distance x 
’ 

