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for the parents of a handicapped child to feel he were trained(why not " taught" ?) by the education committee ratherthan treated by the health committee. The former systemwould have the added advantage that the services of theschool-attendance officer would be available.

These small disagreements in no way detract from mygreat appreciation of the warm-hearted sympathy whichinspires the Royal Commission’s report, and of its excel-lent recommendations.

E. HINDEN.Whipps Cross Hospital.London, E.11.

SPINAL DEFECTS IN HIGH- AND LOW-FLUORIDEAREAS

M. W. P. WARD.

SIR,—I have read with interest the article by Dr. Eleyand his colleagues in your issue of Oct. 12. I note thatthe investigation was sponsored by the Ministry of Healthand took place in 1954. At that time radiologists werenot as conscious of the genetic hazards of radiation asthey are now. Today it would seem unjustifiable tosubmit a fairly large number of normal male children atabout puberty to irradiation of their gonads, which wouldhave been inevitable in this investigation. It would seemthat this investigation could well have been carried out bystudying films taken at hospitals in the area for theinvestigation of possible spinal injuries to casualties.

I hope that the Ministry of Health will not sponsor asimilar investigation again. In the light of the recentwork on the genetic hazards and danger of radiation tothe foetus, I have abandoned the work I was doing onhiatus hernia in pregnancy.

ACCURATE DISPENSING OF OCULENTAAND EYE-DROPS

ARNOLD SORSBYL. J. YARRELL.

Royal Eye Hospital.London, S.E.1.

SIR,—The instillation of oculenta into the conjunctivalsac is a rather haphazard procedure, for the amount ofointment instilled varies considerably, even betweendifferent instillations by the same person. Often as muchor more of the ointment is smeared on to the lids as isintroduced into the conjunctival sac, especially in homeuse when it is applied by those without experience. Like-wise the amount instilled into the conjunctival sac from apipette delivering one or two drops into the sac variesconsiderably, since drops are hardly definite quantities.

In an observation in which three experienced peoplewere asked to instil 1% atropine ointment into the con-junctival sacs of children, it was found that the quantityinstilled varied from 30 to 80 mg. Similarly, with drops of1% atropine sulphate solution instilled into the conjunc-tival sac by experts using different pipettes available atthe hospital the amount varied by as much as 60%. Witha drug like atropine, where the toxicity is relatively low,such variations in dosage probably do not matter much,but this is hardly so with more toxic drugs such as hyoscineand eserine, and more accurate use seems advisable.With this object in view we have had made for us

gelatin capsules containing a fixed amount of ointment(see figure). At present these

capsules are available only with100 mg. of 0-5% atropine sul-phate ointment (+ 10 % overage),so when the whole of one capsule

is delivered into each conjunctival sac a total dose of 1.0mg.of atropine is instilled in the two eyes-the maximumpharmacopceial dose for adults. Used at the frequencyatropine ointment is generally employed at refraction,these applications give adequate mydriasis and cycloplegiaand have two distinct advantages. In the first place, aknown quantity of atropine is instilled, and secondly, theatropine is delivered in sterile form, for each capsule issealed until the end is cut off before instillation.A measured amount of alkaloid, or other highly toxic

agent, can be readily delivered in the form of drops if apipette is used of standardised bore and marked to show

01 ml. This is a, definite quantity, instead of a vague1 or 2 drops. If 1% solutions are used, 01 ml. contains1 mg. of the agent, so a, known quantity is administered,Atropine eye ointment dispensed in gelatin capsules

for refraction purposes would, according to a commonroutine, involve issuing to the patient 16 capsules, 1 being ;used in each eye twice a day for four days. Dispensing

’

in capsules is likely to be slightly more costly than dispensing in small sterilised collapsible tubes, as recom.

mended by the pharmacopoeia, but that may be balancedby a saving from a reduction in the amount of ointmentdispensed. Glass pipettes, with a standard bore markedat the level of 0.1 ml., cost no more than the pipettesgenerally available. They may lead to some saving in thequantities dispensed, for with the delivery of 1 or 2 dropsfrom the pipettes commonly used there are probably fiveor more drops left in the pipette and wasted.We are indebted to Messrs. R. P. Scherer, of Slough, for

making a generous supply of the gelatin capsules containingatropine. The graduated pipettes are manufactured by TheAnchor Glass Company Limited, London, N.W.2.

1. Gregg, D. McC., Allcock, J. M., Berridge, F. R. Brit. J. Radiol.1957, 30, 423.

2. Pontasse, E. F., Humphries, A. W., McCormack, L. J., Corcoran.A. C. J. Amer. med. Ass. 1956, 161, 149.

3. Hodson, C. J. Proc. R. Soc. Med. 1957, 50, 539.

RENAL FAILURE FOLLOWING AORTOGRAPHY’ SIR,—Dr. Samuel and Dr. Denny say in their letter’

(Sept. 21) that aberrant (accessory) renal vessels are notdemonstrated by selective renal angiography. This isnot strictly correct, for they are in fact demonstratedindirectly in the nephrogram by the presence of a zoneof non-opacincation, usually polar in distribution, andselective catheterisation of the accessory vessel may thenbe undertaken ; it is only if this vessel is hypoplastic that,catheterisation may be difficult and a renal aortogramisthen nece8Rary.1For the investigation of the renal aspects of hyperten.

sion, particularly hypertension due to occlusive renalarterial disease, it is obviously necessary to have bilateralassessment of renal arterial architecture, especially theproximal parts of the renal arteries ; ; therefore renalaortography is essential.2 But it is also necessary tohave clear, detailed and unobscured sight of the smallerintrarenal arterial branches,3 which is not always achievedby retrograde renal aortography owing to masking bythe overlying coeliac axis and mesenteric branches.1 Thiswill almost certainly happen if the catheter-tip is sitedabove renal-artery levels. We have seldom failed to getretrograde filling of the renal arteries by placing thecatheter tip 1-2 in. below the hila of the kidneys, whetherwe have used mechanical or manual injection speeds andpressures. This observation is based on experience ofthe retrograde method of aortography over the pastthree years. I am sure Dr. Samuel and Dr. Dennvconcede that the demand for renal aortography for theinvestigation of hypertension is not as great as it is forthe elucidation of other renal lesions in which selectiverenal arteriography is undoubtedly the method ofchoice, but we have not suggested that the selectivemethod is the only practical method of all forms of renalangiography. 1When the reduction of chemotoxic effect by selective

renal arteriography is considered, it is not only theknown small volume (about 4-6 ml.) of contrast mediumwhich is important but also the low concentration (30%).We also believe that medium and blood mix freely, as issometimes shown by " streamlining " appearances inthe renal artery, before dissemination in the renal parenchyma ; but an unstable catheter tip in retrograde renal ’

aortography may result in a large and unknown volume