~ May 21, 1885] 
NATURE 
51 
the description of the underground workings is scarcely 
sufficient to enable the reader to appreciate exactly the 
value of the author’s theoretical conclusions. 
ils JB, 
OUR BOOK SHELF 
Den Norske Nordhavs-Expedition, 1876 to 1878. XIII. 
Spongiadae. Ved G. Armauer Hansen. 25 pp.,7 plates, 
I map. (Christiania, 1885.) 
THE thirteenth report on the zoological collections of the 
Norwegian North Sea Expedition treats of the sponges, 
and is by one who, though well known as a student of 
other branches of zoology, has not, we fancy, been hither- 
to known as a spongologist. We do not know whether 
we may not associate with this fact the somewhat alarm- 
ing percentage of new species which he describes ; of the 
forty-five enumerated, thirty, or two-thirds of the whole, 
are new ; many of the species, among which it is interest- 
ing to note there is a new Hyalonema, H#. arcticum, are 
very briefly described ; on the other hand, the figures, as 
in other parts of this report, are well executed, and will 
be of considerable assistance in the detection of the 
species by other workers. The author was, unfortunately, 
unable to obtain any preparations in which he could 
trace out the canal system, or the structure of the soft 
parts, and he has, therefore, confined himself to an 
account of the spicules. With regard to these he has, 
we are glad to note, made use of the stenographic system 
which was invented by Dr. Vosmaer ; any and every pro- 
position for abbreviating the descriptions of species ought 
to be tested, for the abundance of “literature” is a very 
threatening danger to science. It is not likely that all 
the methods that have been from time to time suggested 
will be found to be useful; no one, for example, has fol- 
lowed the two methods proposed by the late Prof. Garrod, 
or that adopted by Prof. Jeffrey Bell in the description of 
species of starfishes; on the other hand, Dr. Herbert 
Carpenter has taken up and improved the method sug- 
gested by Prof. Bell for the species of Comatulids, and 
will, we understand, adopt it in his forthcoming Chadlenger 
Report. The chief objections to formule as applied 
either to species, or spicules, or other organs, are, of 
course, that a particular method has to be learned, and 
that, if it is too brief, it tells us too little. The latter, for 
example, is true of the Owenian method of formulating 
the dental characters of Mammalia ; it tells us that, while 
Gymnura has eight premolars above and below, Erizaceus 
has six above and four below, but it does not tell us which 
are missing in the latter. If we desire to register our 
knowledge on this point, we must make use of the more 
elaborate system devised by Prof. Flowerand Dr. Dobson. 
As to the former objection, we must bear in mind that some 
spicules have had such names as floricomo-hexradiate, or 
patento-ternate, applied to them, and we can well imagine 
that a formula may well be accepted as a not unpleasant 
alternative. 
The Hunterian Oration. Delivered at the Royal College 
of Surgeons, by John Marshall, F.R.S., &c. (London: 
Smith, Elder, and Co., 1885.) 
Not only the wide range and perennial importance of 
the work of John Hunter—the surgeon and anatomist 
whom the clear judgment of Buckle places second only 
to Aristotle among inquirers into organic nature—but 
also the fertility of human ingenuity, is shown by the fact 
that, for nearly a century, every year has seen some 
eminent surgeon discourse with more or less variety and 
freshness upon the life and achievements of this graet 
man. 
The novelties of Mr. Marshall’s treatment of the well- 
worn theme are, first, recounting the life of his hero 
backwards in successive decennia from his grave to his 
cradle ; and, secondly, bringing Hunter into the modern 
world of science, and imagining the way in which he 
would be affected by modern methods and modern results. 
No’ doubt he would be delighted to see the splendid 
collection which has grown out of his “ Hunterian 
Museum,” but whether he would be more pleased or 
puzzled by the technics of histology and the elaborate 
machines of a physiological laboratory may perhaps be 
doubted. 
An orator must be an eulogist, and in this case 
there is ample room for praise ; but it would be a valu- 
able contribution to criticism if Mr. Marshall, or some 
equally qualified man, would discuss Hunter’s achieve- 
ments as an anatomist, compared with Meckel and 
Cuvier; as a surgeon, with his contemporary Pott, and 
his successors Astley Cooper and Brodie; as a physio- 
logist with Haller and Bichat; and as a naturalist—on 
the broad ground which includes human and “ compara- 
tive” anatomy, normal and morbid structure, “the 
physiology of disease” (to use Hunter’s own phrase), as 
well as that of health—with the only successor he has 
had, or, we may predict, ever will have, the illustrious 
Johannes Miller. 
To such a critic might be suggested as shades in the 
intellectual portrait, Hunter’s neglect of the aid of magni- 
fying glasses such as were used to good effect before 
him by Leewenhoeck and Grew ; his want of learning 
and cultivation, with a certain consequent narrowness of 
mind ; and such occasional obscurity of language as may 
not unfairly be taken to imply some obscurity of thought. 
“ Definitions,” he says, “ of all things on the face of the 
earth are the most cursed.” But may not the use of 
terms without definition sometimes excuse a choleric 
word ? 
After the most exacting criticism, there is no question 
that Hunter’s name would remain one of the glories of 
this country—to be mentioned next to those of Harvey, 
Newton, and Darwin. It is therefore most fitting that 
his fame should be kept green by the annual piety of 
successive orators, and of these Mr. Marshall is a worthy 
compeer. 
LETTERS TO THE EDITOR 
[Zhe Editor does not hold himself responsible for opinions expressed 
by his correspondents. Neither can he undertake to return, 
or to correspond with the writers of, rejected manuscripts. 
No notice is taken of anonymous communications. 
[Zhe Editor urgently requests correspondents to keep their leiters 
as short as fossible, The pressure on his space ts so great 
that tt is impossible otherwise to insure the appearance even 
of communications containing interesting and novel facts. 
Notes on the Action of the Wimshurst Induction 
Machine 
AN interesting notice on the different influence-machines now 
in use occurs in NATURE, vol. xviii. p. 12. Ofthese ingenious 
instruments, that lately devised by Mr. Wimshurst is likely to 
recommend itself beyond others, on account of the ease with 
which it may be excited, even in a damp atmosphere, and the 
high tension of the electricity discharged from its accumulators. 
The following remarks lay no claim to originality, but they 
may neverth«less afford some interest to those who would 
witness its effects at a small pecuniary outlay ; indeed its con- 
struction is well within the powers of the amateur mechanic. 
Makers advertise sparks of fabulous length from comparatively 
small machines, but dense discharges of 44 inches may be 
obtained under favourable circumstances from disks of 15 inches 
diameter, if care be taken adequately to insulate the collecting 
apparatus. It is obvious that an zmassisted spark of 9 inches 
cannot be produced from plates whose minimum air-spaces of 
insulation do not exceed 34 inches. The weakest part of insula- 
tion in these machines is usually between the metal inductors 
and the attachments of the driving-gear and spindle. In the 
dark, beautiful brushes of light flash across these spaces, and 
thus they point where the electricity leaks away from the 
