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7 firm applications for commissions and 17 for medicalcadetships.

In the House of Commons on June 6, the Secretary ofState for Air, Mr. Julian Amery, was asked about theresponse as seen in the R.A.F. medical and dental branches.He said it had been " distinctly encouraging ": there hadbeen 650 inquiries and over 60 firm applications, com-pared with 12 inquiries and 2 applications in the sameperiod of last year.

THE SURGICAL KNOT

THE first thing the budding surgeon does to preparehimself for his life’s work is to retire into a comer and tiebits of string round a button in his white coat. He islearning to tie knots speedily, scorning the " granny " andadopting the

" reef ", and he is also recapitulating thehistorical development of his art. For the objective-thestaunching of blood-must be one of the most ancient ofsurgical rites.This time-consuming, tedious, and sometimes difficult

surgical manoeuvre has changed little since earliest days.From time to time accounts of finicky little instruments,designed hopefully to mechanise a hand-made job, appearin surgical journals. But the prototypes find their way todusty cupboards reserved for discarded instruments.Some surgeons dispense almost entirely with ligatures anduse diathermy-a modem variation of cauterisation withboiling oil. But large vessels cannot safely be dealt withby this method, and many surgeons dislike it because ittends to favour the collection of serum in the wounds.Metallic clips, which are popular with neurosurgeons (andwhich also date from the remote past), have a limited use-fulness. On the whole most surgeons seem content to relyon manual dexterity achieved with practice.

Willis Potts 1 describes a method whereby the surgeonholds the haemostatic forceps vertically by its middle,the assistant loops the ligature around its tip, and thesurgeon lets the forceps drop on its side, whereupon theassistant ties the knot. Obviously this manoeuvre is noteasily applied in the depths of a wound. But for incisionalwounds it seems simple and easy to learn.A good knot depends on the ligature material. This,

too, has changed little over the years, except for theintroduction of nonabsorbable synthetic substances.

Catgut (universally popular) is slippery and not so easy tohandle as silk or linen thread which produce less tissuereaction and give firm and non-yielding knots. Some

surgeons swear at (and less often by) the material of theirchoice; but so long as patients bleed when tissues aresevered there will be a need for surgical knots and some-one to tie them, whether it is the surgeon or his assistant.No machine seems likely to displace them.

SCINTILLATION RADIODIAGNOSIS

Two technical developments in the diagnostic use ofradioactive tracers were reported by Brownell and Sweet 3in 1953. The first was the detection of positrons byscintillators placed on opposite sides of the head andrecording only when stimulated simultaneously (withinnarrow limits). The second was a method of detectinggamma rays and of recording only the difference between

1. Potts, J. W. J. Amer. med. Ass. 1962, 180, 494.2. See Lancet, 1961, ii, 416.3. Brownell, G. L., Sweet, W. H. Nucleonics, 1953, 11, 41.

counting-rates on the two sides of the head. Botterellet al. have now described their use of these methods overfour years; they employed the same technique throughoutand used ’4as in the form of sodium arsenate. Tumourswith the greatest cellularity seemed to retain the isotopein greatest concentration. The highest values were inmeningiomas, followed in order by glioblastomas, meta-static carcinomas, and astrocytomas. Unlike radioactiveiodinated human serum-albumin 5 6 the isotope did notbecome concentrated to any detectable degree in subduralhaematomas or arteriovenous malformations. In thedetection of meningiomas this method contrasted withelectroencephalography: the latter might fail to reveal thisextrinsic tumour but nearly always indicated an intrinsictumour.

Angiography may also fail to outline positively a

sphenoidal wing meningioma, and, because of obstructionat the opposite foramen of Monro, ventriculography inthis condition can be highly dangerous. Had the scintil-lation method no other justification, this alone wouldrecommend its provision in appropriate centres. One ofthe most important tasks in neurosurgery is to detect, asfar as possible, every benign tumour at an early enoughstage to ensure complete recovery of the patient. This cannow be more nearly achieved if clinical acumen is exer-cised properly and neurosurgical facilities are ample.Neither of these requirements has been met in the

past.8 9

GROWTH HORMONE

THE species specificity of preparations of growth hor-mone from different animals formed a stumbling-blockto study of the action of this hormone in man. Eventuallyit was shown that only primate growth hormone wasactive in man; and since then much work has been doneon its metabolic effects.1o

Growth hormone is not concerned solely with somaticgrowth: it is produced by the pituitary throughout life,and is a general metabolic hormone. It causes synthesisof protein, which is reflected in retention of nitrogen inthe body, and along with this a proportionate retention ofthe mainly intracellular electrolytes-potassium and

phosphorus. It also causes retention of sodium andchloride, largely extracellular, and hence expansion ofextracellular-fluid volume. These changes seem to beindependent of the secretion of aldosterone, and growthhormone has no immediate effect on blood-pressure. It

might be expected to cause consistently a retention of cal-cium in the skeleton, but changes in calcium balance havebeen variable and the serum-alkaline-phosphatase is

usually unaffected.Growth hormone also has an important effect on carbo-

hydrate metabolism by impairing glucose tolerance andincreasing resistance to insulin: under its influence dia-betics rapidly develop gross glycosuria. It has a directaction on fat metabolism in the normal (and particularlyin the fasting) individual, mobilising non-esterified fattyacids and ketones; and in the diabetic it rapidly causesgross ketosis.

4. Botterell, E. H., Lougheed, W. M., Morley, T. P., Tasker, R. R., Paul, W.Canad. med. Ass. J. 1961, 85, 1321.

5. Chiro, G. di. Acta radiol., Stockh. 1961, suppl. 201.6. Lancet, 1961, ii, 1186.7. ibid. 1961, i, 1388.8. Segelov, J. N., Davis, R. Med. J. Aust. 1961, ii, 1.9. McKissock, W. J. Neurol. Psychiat. 1961, 24, 296.10. See Finkel, M. J. Amer. J. Med. 1962, 32, 588.