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catalogue of peculiarities must be added a later observation that they are usually resistant to neomycin and bacitracin. Jevons and his colleagues have now compared 34 of these untypable strains from various countries with 22 native strains of phage-type 83A .27 The majority of both groups are resistant to most of the commonly used antibiotics, but judged by the cultural characters mentioned above there is a relative but not an absolute distinction between them. It would be convenient if one could believe that a new strain of staphylococcus (if that is not begging the question) spreads round the world like an influenza virus. Unfortunately it is almost certain that these untypable strains arose almost simultaneously in three continents. Those found in western Europe probably arose from type-83A strains with which they have much in common. The origin of the others is a mystery which is now beyond solution, but resistance to neomycin and bacitracin suggests that the persistence in the hospital environment derived from these qualities gives opportunities to acquire a" blocking " bacteriophage. Bacitracin came into use in the mid-’50s, and neomycin somewhat earlier; but there are so many unknown quantities, and perhaps such an element of chance, that no-one would care to construct a timetable of bacterial evolution on this evidence. It is odd, however, that Staphylococcus aureus, the organism most commonly isolated in hospital laboratories everywhere, should show so few variations from the type. It is evidentlya successful parasite.
arteries and veins, and was absent from Wharton’s jelly, placental extracts, and umbilical arterial and venous blood. The substance has been characterised sufficiently for it to be distinguished from the vasoactive polypeptides on pharmacological grounds, and to be recognisable as a lipid-soluble unsaturated hydroxy-acid. It may well prove to be allied to the prostaglandins-lipid-soluble substances which are present in various tissues and which evoke contraction of smooth muscle. 34 Whether it is released after delivery, and is responsible for the normal closure of the umbilical vessels, has still to be determined.
LATE-NIGHT EDUCATION
TELEVISION audiences are measured in millions but there are only 100,000 names on the Medical Register. This is why the use of public channels to present medical advances and refreshment to the doctor at his fireside must be assessed carefully and continuously. In February we mentioned some reactions to the B.B.C.’s " Medicine Today 35"; and now an inquiry has been conducted into the medical items on the Scottish commercial channels which have been broadcasting such programmes since March, 1963.36 Late on a Monday evening in April, 1965, viewers in the catchment areas of Scottish Television Ltd. and Grampian T.V. were able to see a half-hour programme on backache. Doctors in this area were asked to record their reactions to the method and to this programme in particular, by taking part in a postal survey. The response was poor-only 16% of doctors replied, and only half of these had seen the programme. Most non-viewers CLOSURE OF UMBILICAL BLOOD-VESSELS SEVERAL factors may account for the constriction of the either could not receive the signal or found its time of umbilical blood-vessels which follows delivery of the arrival (11 P.M.) inconvenient. The majority opinion was mammalian foetus. Changes in temperature 28 and oxygen that the programme was instructive, interesting, not too tension of the perfusing blood 29may be partly responsible, academic, and of value in practice. This immediate but the most important cause has been generally assumed reaction is encouraging, but, based as it was on a nonrandom sample of 387 out of a possible 5000 doctors, the to be the mechanical stimulus of tearing of the vessels which results can be of slight value in the long-term assessment promotes a powerful contraction of the vessel walls.3O The umbilical vessels are devoid of nerve-supply, and therefore of television in postgraduate education. Discussing " Medicine Today ", we noted that " the the constriction must either result from an intrinsic effect precise target of the series has yet to be defined ". The or be mediated through some humoral agent. Umbilical vasoconstriction is brought about by several pharmaco- influence of having a specific audience in mind is underlined Bell and Shaw’s results.36 The Scottish series was logically active substances, including the catecholamines, aimedby at the general practitioner; and fewer hospital dochistamine, posterior-pituitary extract, and 5-hydroxy- tors the backache programme of value in their tryptamine.31 The response of the placental and umbilical workthought and more found it too superficial. vessels to 5-hydroxytryptamine may be so great as to The use of public television in postgraduate medical interrupt pregnancy in species such as the rat, mouse, and education is no longer experimental: it has been in use rabbit.32 Possibly, therefore, the release of such a chemical for 13 years in the U.S.A., for over 3 years in Scotland, substance after delivery may cause the vascular changes and since January, 1965, in England. Thus there has in the umbilical cord. In order to investigate this further, a wealth of material, which it may now be too late been 33 Karim has studied aqueous extracts of human cords, to use (for such research as has been done has been and found that they contain a substance which stimulates soooth muscle, causing contraction of preparations of rat mainly on traditional audience-analysis lines rather than colon, guineapig small and large intestine, rat uterus, and on the effects on a doctor’s daily practice). The appointrabbit ileum. It also caused contraction of isolated ment by the Association for the Study of Medical Educaresearch fellow to examine the project is a useful Umbilical-artery preparations and isolated human myo- tion of abut start,37 he, and any other interested parties, will have metrium. It was present only in the walls of umbilical many difficult problems. Medicine has been the guinea27. Jevons,M. P., John, M., Parker, M. T. J. clin. Path. 1966 19, 305. 28. Haselhorst, G. Z. Geburtsh. pig in this approach to postgraduate education: useful Gynäk. 1929, 95, 400. W. ibid. 1927, 90, 559. 29 Schmitt, assessments can only be made with the full cooperation of 30 Starling and Lovatt Evans’ Principles of Human Physiology (edited by the doctors in the audience. H Davison and M. G. 1962. Eggleton). London,
31. Panigel, M. J. Physiol., Paris, 1959, 51, 941. 32. The Pharmacological Basis of Therapeutics (edited by L. S. Goodman and A. Gilman). New York, 1965. 33. Karim, S. M. M. Nature, Lond. 1966, 211, 425.
34. 35. 36. 37.
Horton, E. W. Experientia, 1965, 21, 113. Lancet, 1966, i, 415. Bell, A. E., Shaw, G. Scott. med. J. 1966, 11, ibid. p. 258.
250.