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mouth disease in a wild hedgehog has so far beendemonstrated. Mr. I. A. Galloway at the NationalInstitute for Medical Research has shown thatcats are susceptible to experimental inoculation-which agrees with independent work by Hove inGermany. He has studied 90 substances of veryvaried chemical composition in the hope of findingone which would prevent or modify the disease,but without success. A similar series of negativeexperiments has recently been recorded fromWaldmann’s laboratory. Mr. Galloway has alsoshown that the virus survives in milk about as

long as it survives in tap water, except that whenthe milk becomes sour activity is soon destroyed.Virus added to sterilised milk will remain activeat 18° C. for 30 to 35 days.With a view to making a vaccine of greater

efficacy than the formalinised virus previouslyshown to produce immunity in guinea-pigs, othermeans of destroying its infectivity have beentested, but with neither phenol, heat, ultra-violetrays nor bile could an equally serviceable vaccinebe obtained. Mrs. Gibbs has made furtherobservations on the preparation of vaccine withformalin and has studied the duration and qualityof the immunity produced by the vaccine in

guinea-pigs. Prof. A. Ciuca shows that comple-ment fixation can be carried out with immuneserum and concentrated virus, and that the serumproduced with each of the three types of virus isquite specific for its own type in this reaction,as was already recognised when such sera wereused for the neutralisation of the virus in experi-mental infection. It is clear that a trivalent ormultivalent serum is necessary for practical purposesunless the presence of only one type of virus can beassured at the time and place at which it is needed.The physical properties of the virus have been

further studied, and Prof. H. B. and Dr. M. C.Maitland record its successful cultivation invitro in the tissues of the embryo guinea-pig,finding that not only surface tissues of the tongue,lips, and plantar pads, but also the hairy skinform a suitable pabulum. Cultivation was carriedon for nine months in a single series of 17 cultures ;in the final flask the virus could be diluted 10,000times and still prove infective, the calculated totalmultiplication reaching the figure of 1039 times theoriginal inoculum. Dr. Edwards has investigatedthe desiderata for culture in another way, examiningthe best conditions for survival of the virus with

special regard to the acid-base. and oxidation-reduction states of the artificial media. He hasnot obtained evidence of multiplication, butrecords results showing, inter alia, that the

optimum pH for survival is not the same when otherconditions are varied, and that the pH in thedeveloping vesicles on the guinea-pig’s foot ismuch more acid than has hitherto been regardedas essential for survival. The types of differentsamples of virus from British and Argentinesources have been examined by Dr. Andrews andhis co-workers and they have mostly correspondedto the types previously recorded, but a few aberrantstrains have been found.

It may be said that from the practical point of

view much knowledge has been gained concerningthe means by which the disease may be spread,and this should help to anticipate and discount,danger from previously unknown sources of infec-tion in spite of the increased facilities for distribu-tion of the virus by the ever-growing means oftransport. From the theoretical aspect it is

interesting that the infective agent of foot-and-mouth disease, which is perhaps the smallest of thepathogenic viruses, nevertheless is not veryunlike the infective bacteria in its power ofresistance to physical and chemical substancesand in its relation to the immunity reactions whichit elicits.

THE SHORTAGE OF DENTISTS.SPEAKING from the chair at the annual prize

distribution of the Birmingham University DentalSchool, Mr. Malcolm Knott said that the countrywould soon be faced with a serious shortage of dentists.If the health of the country were to be properlyattended to there must, he said, be a considerableaddition to the number of those now entering thedental profession. To make good the loss on theDentists’ Register by death and retirement frompractice an annual addition of 625 names was needed ;and, as a matter of fact, we were not getting anythinglike that number. School clinics alone could absorb500-700 dentists. His anxiety has been shared bythe Dental Board for many years. It is a simplearithmetical point with which, as Sir F. D. Aclandhas said, anyone is bound to be impressed. Whatnumber of students should enter our dental schools

each year in order to maintain a register of over14,000 if, before the war, 250 new licentiates a yearwere needed to maintain a register of about 5000 ?The arithmetical answer to this rule-of-three sum,he said, is 700. And as the annual entry to theschools is not more than half this figure, two coursesof action have been forced upon the Dental Board :(1) to help to rebuild and equip dental schools so asto make them more efficient and less unattractivethan they (sometimes) used to be ; and (2) to helppromising young people, likely to make good dentists,who cannot afford the necessary training. In bothdirections this policy has been cQnsistently pursued.Only this week we record the fruition of the schemewhich gives Newcastle-on-Tyne a new dental hospitaland school adjoining the Royal Victoria Infirmary.The scheme of assistance has steadily gone on;bursaries are tenable at any recognised dental schoolin the British Isles, and the Board’s bursars are

regarded as comparing favourably with other studentsin regard to personality, industry, and social standing.The Registrar of the Board has prepared a memo-randum which has continuously been brought to thenotice of headmasters and others in a position toinfluence the careers-of boys and girls leaving school.In presenting the prizes at Birmingham Prof. C. S.Gibson remarked that the real need was the develop-ment of something which would make dentistry morethan a mere craft. He would like to see the curriculumof dental schools altered with a view to fosteringresearch work in dentistry ; in his own departmentat Guy’s grants had been given towards elucidatingthe mysteries of metallic alloys for fillings and ofthe materials used in the making of dentures. Thefuture was bright with promise for the dental studentsince the range of openings for junior practitionersof dentistry had been greatly augmented.