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but it may be of considerable functional importance.Weed’s observations suggest that its action on the

blood-supply to the brain may resemble somewhatthe suction feed of petrol to a modern motor engine,.ensuring an adequate supply and safeguarding thebrain from the effects of any rapid fall in arterial

pressure. He draws attention to the fact that acraniotomy removes this safeguard so that rapidalterations of the position of the body are less easilycompensated. The clinical implications of this work..have not yet been fully studied, but it obviouslyhas important bearings both on cerebral surgeryand on the treatment of traumatic and vascularlesions of the brain.

EXPERIMENTAL EMBRYOLOGY AND THE

NERVOUS SYSTEM

THE nervous system is early laid down andelaborated in the growing embryo, and early showsa high degree of regulability and dependence uponinternal factors. For these reasons the methodsof experimental embryology have had peculiarsuccess in the study of the many problems presentedby nervous structure and function. Prof. Ross G.Harrison chose this subject for his Croonian lecturebefore the Royal Society on June 29th and describedmany interesting observations on the embryo whichhave enlarged our knowledge of neurology. Theold controversy as to whether form determinesfunction or function form has received a striking,contribution from the fact that complicated neuro-muscular mechanisms are completely laid down in/the vertebrate embryo long before they begin towork. In the amphibian, where they work muchearlier, their activity can be suppressed by meansof chloretone without in any way interfering withtheir development. Embryological study also playedan important part in the establishment of the cell

theory, or in more technical words, the neurone

concept; in the amphibian embryo it was shownthat ganglion cells were essential while sheath cellswere not, thus indicating that the nervous units areautonomous. The growth of nerve-fibres from thecell by means of amceboid acitivity has been actuallywatched in tissue-culture, and this experimentsettled the question of whether fibres grew out fromthe young neuroblast or were the result of differentia-tion of pre-existing protoplasmic bridges. The out-

growth is more or less haphazard, but can be controlledby altering the structure of the fibrin clot in theculture medium and so producing tension. In thisway the outgrowing fibre can be persuaded to formplexuses. Chemical stimuli, however, have not yetbeen shown to exert any influence on the growingfibre, although theoretically they would seem mostlikely to play a part. In the living embryo thecourse and final fate of the outgrowing fibre isdetermined by the peripheral structures which it

meets, as is interestingly shown by limb-grafts.If the limb of a large salamander is grafted on toa small salamander, the nerve-supply of the limbis provided by the host, but its arrangement is thatof the animal from which the grafted limb came-i.e., the nerves are correspondingly large, the sensorynerve-fibres and spinal ganglion cells being actuallyincreased in number while the motor nerves are

adjusted by more frequent division than usual ofthe small salamander’s axones. There seems to besome kind of attractive influence from the periphery ;when a limb is shifted forward or backward on theanimal the nerves normally supplying it tend to

converge upon it. If a limb is prevented from

developing, its spinal ganglia show hypoplasia, butif a limb is grafted out of place the ganglia showhyperplasia. The motor centres are not similarlyaffected, though the size of their cells may be reducedor increased. Thus hyperplasia and hypoplasiaare the result of incoming rather than of outgoinginfluences, and the developing nervous systemresponds to a great variety of changed conditions.Further study along these lines will surely yieldfruitful results.

ARTHRITIS

So much has been written about rheumatismin the last few years that few would care to saywhich views have been justified and which dis-credited. The British Medical Association’s com-

mittee have done a real service in producing a shortreport 1-no more than 19 pages-on the causationand treatment of arthritis and allied conditions,which gives a clear, balanced, and comprehensivesurvey of our present knowledge of this importantgroup of diseases. In addition they survey thenational schemes for treatment already in practicein Holland, Germany, and Sweden, and set out a

suggested scheme for Great Britain together withproposals for future research. The persistence oftheories which have no valid foundation is an obviousbar to progress, and the committee have done theirbest to bring the facts into the light of day. Theypoint out, for example, that the idea that arthritisis due to an excessive accumulation of lactic acidin the body is now regarded as incorrect and that thelactic acid in the blood, urine, and sweat of arthriticsubjects shows no material variation from that seenin non-arthritics. Further, they say that an acidreaction of the skin is found in non-arthritics as wellas in arthritics, and the change in the reaction ofthe skin during a hot-air or vapour bath is a normalphysiological process. Again, the division ofrheumatic disease into two groups, according to anacid and an alkaline diathesis, gains no support fromwell-controlled experiments. Since R. Pemberton,of Philadelphia, and his co-workers showed thata majority of rheumatoid arthritis patients have adefinite glucose intolerance, this finding has oftenbeen interpreted as due to a defect in the pancreas.This interpretation, however, is incorrect because,as Pemberton emphasises, the defect is in the tissuesthemselves and in their blood-supply, and owingto vasoconstriction the tissues absorb and store

glucose at a reduced rate. The committee drawattention to the very real value of manipulation incases of arthritis-a form of treatment not nearlyas widely used as it should be. They remark that"the reputation enjoyed by certain irregular practi-tioners might be reserved for the medical professionif a greater interest were taken in this branch of

therapeutics and were technical skill in these methodsmore widely distributed." A section of the reportwhich will be particularly helpful to many is the onedealing with mineral waters and baths. It is

customary to recommend one spa more than another,but in the recommender’s mind there is not always aclear idea why a certain patient will receive morehelpful treatment at A rather than at B for his

particular complaint. Here we have a short descrip-tion of the chemical content of the various waterswith an indication as to which form of rheumatismwill be likely to benefit from which type of mineralwater. It is somewhat depressing to note what alarge part orthopaedic and surgical measures play in

1 Brit. Med. Jour., June 17th, p. 1033.

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the treatment of arthritis, and it is to be hoped thatas time goes on the emphasis will shift further awayfrom them.

THE OLD ASHMOLEAN

A SECOND and greatly enlarged edition of a Guideto the Historic Collections of Scientific Instrumentsand Kindred Objects, in the Old Ashmolean at

Oxford, has been prepared by the curator, Dr. R. T.Gunther, and was issued on the 250th anniversaryof the opening of that museum by the Duke ofYork on May 21st, 1683. The earlier edition,which appeared under the title of "Historic Instru-ments for the Advancement of Science " and wasreviewed in THE LANCET for Jan. 2nd, 1926, dealtprincipally with the Foundation Collections givento Oxford by Dr. Lewis Evans in 1925, which wereprincipally mathematical and astronomical and didnot include many items of medical interest. Itserved, however, as a nucleus round which has

gathered scientific material of all kinds, thoughprincipally relating to work done in Oxford. Amongthese accessions are the Clutton Collection of MateriaMedica, comprising 1032 specimens purchased fromJoseph Clutton, of Holborn, for :E21 6s. 8d. in 1729,perhaps the oldest intact collection of its kind ofancient date in the world, and the even earlier

teaching collection of physical drugs, formed byJohn Pointer, of Merton College, and used byhim for instructional purposes about 1715. Theseries of microscopes on exhibition includes manyof special interest from the facsimile of the originalHooke instrument about 1665, by means of whichcellular structure was first recognised and delineated,to more recent types of achromatic instruments,such as the Pillischer stands used by Sir Henry Aclandwhen, with Victor Carus as his demonstrator, heintroduced the practical teaching of histology andmicroscopic anatomy into Christ Church, and so

into Oxford. Of special value is the picked seriesof achromatic object glasses by the best makers,specially chosen by Mr. E. M. Nelson to illustratethe principal stages in the evolution of this essentialadjunct to the microscope. A typical collection ofinstruments drawn from the duplicates in the col-lections of the Royal College of Surgeons of Englandis now being extended by more recent acquisitionsfrom the Radcliffe Infirmary and from privatesources. So that in time Oxford may also come topossess a select, if not a large, collection of historicsurgical instruments. And thus may be materialisedfor the first time in two and a half centuries theintention of Elias Ashmole, the founder of themuseum: "Because the knowledge of Nature is

very necessarie to humaine life, health and theconveniences thereof, and because that knowledgecannot be soe well and usefully attain’d, except thehistory of Nature be knowne and considered ; andto this, is requisite the inspection of particulars,especially those as are extraordinary in their Fabrick,or usefull in Medicine. I Elias Ashmole, out of myaffection to this sort of Learning, wherein myselfehave taken, and still doe take the greatest delight ;for which cause also, I have amass’d together greatvariety of naturall Concretes and Bodies, and bestowedthem on the University of Oxford."

ANIMAL RESEARCH IN TROPICAL MEDICINE

THE necessity of animal research for the progressof medical and veterinary science has been accepted,however unwillingly, by most of those who have totreat sick men and beasts. Nevertheless, so long asthere are people who try to stop this important work

so long must the annual Stephen Paget memoriallecturer repeat the story of our indebtedness to

experimental science. Sir Leonard Rogers, deliveringthe seventh lecture on June 22nd, declared boldlythat more specific curative remedies for serious wide-spread disease have been discovered by animal

experiments in about 30 years than accrued from3000 years of empiricism, and illustrated his thesisfrom the field of tropical medicine. As the resultof a few almost painless experiments, he said, thesuccess of permanganate of potash in saving thevictims of snake-bite was established, but even theseexperiments were postponed for nearly 30 years bythe efforts of anti-vivisectionists, to whose door mustbe laid the deaths of an uncounted number of victims.of snake-bite in the interval. The case-mortality ofcholera has been reduced from 59 to 20-8 per cent.by the use of intravenous injections and perman-ganate pills, the clue to the use of the pills havingbeen furnished by those same experiments whichwent so far towards solving the terrible problem ofsnake-bite. Moreover, it is now possible to protectaltogether a very large proportion of inoculated

subjects. The only specific curative treatment forbacillary dysentery is the antitoxic serum obtained

through the horse, while amoebic dysentery, andassociated liver abscess, can now be treated scienti-fically as a result of experimental work. The modernmethods of attacking plague are based on experi-ments with vermin on whose destruction large sumsare annually expended, yet the opponents of vivi-section would apparently prefer their rats and miceto be exterminated by poison or gas rather thanthat a few of the doomed should die painlessly in alaboratory for the salvation of thousands of men,women, and children. Sir Leonard showed how

during the European war enteric fever was displayingan alarming tendency to spread until the heroic

propaganda work of Stephen Paget induced thesoldiers to submit voluntarily to the preventiveinoculation which would have been made compulsorybut for the agitation against it. The modern com-pounds which are giving us the upper hand in thefight against sleeping sickness, which has for manyyears been decimating Africa, are largely due to

experiments on rats and mice, and similar researcheshave provided the means of eradicating kala-azar,which carried off one-third of the population of theBrahmaputra valley of Assam in the course of30 years. And so the story goes on, through bilhar-ziasis, hookworm disease, and malaria, to the manydiseases of animals themselves which have beenmastered as the direct result of animal experiment.Sir Leonard mentioned rinderpest, haemorrhagicsepticaemia of cattle, blackquarter, anthrax, swine

erysipelas, and distemper to show the debt of animalsto experimental work. It must certainly be heldunreasonable to dispute the fact that beasts as wellas man have been saved much suffering by thiswork.

THE third International Congress for ExperimentalCytology will be held at Cambridge from August 21stto 26th. The international president is Dr. TheodorHuzella, professor of anatomy in the University ofDebreczen, in Hungary, and the local presidentMr. James Gray, F.R.S. The main subjects of discus-sion will be cell respiration and cell metabolism,cell form and function, the electrophysiology of thecell, Entwicklungsmechanik und Explantation, andthe cultivation of animal and plant viruses. Thelocal secretary is Miss Honor Fell, D.Sc., StrangewaysResearch Laboratory, via Cherryhinton, Cambridge.