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obstetric physiology and supported by midwives or

technicians trained and equipped to measure uterine

forces, control infusions on a rational basis and diagnoseimpending foetal distress. Such a service is needed roundthe clock. So often funds are short because those incontrol of policy are unaware of the clinical value ofrecent obstetric research. There is a real need for a

centre at which the benefit of physiological measurementscan be demonstrated to the obstetrician and also to themidwife.Mr. Williams performs a service in again reminding

readers to make the gravitational correction if the intra-uterine pressure is not measured at the highest point ofthe uterus when the patient is supine. Unfortunately, hehas misquoted our intentions when he writes that thehand is to be preferred to objective measurements. Wefind no evidence that man is endowed with an absolutesense of pressures, or sense of urgency for prevention ofperinatal mortality or morbidity.

W. C. W. NIXONC. N. SMYTH.

Obstetric Hospital,University College Hospital,

London, W.C.1.

THE PREMATURE PERSUADERS

SIR, Your leading article of Jan. 27 has been criticisedin an interesting article in The Chemist and DruggistFeb. 3. This editorial questions your view that controlledtherapeutic trials should be done before a new drug ismarketed, and states quite correctly that all reputablepharmaceutical firms carry out extensive animal toxicitytests and clinical trials before marketing new drugs. Theircriticism is, I think, due to a failure to appreciate thatuncontrolled clinical trials cannot, except in a few rareinstances, show whether a new drug is or is not moreeffective than existing remedies. In the absence of clearevidence on this point, it is not justifiable to use any newdrug other than in exceptional circumstances for there isalways a possibility of harm being done to patients of thesort which cannot be shown by animal toxicity tests or byordinary short-term clinical trials. Even if a properlycontrolled therapeutic trial has shown that the new drugis of value, and despite satisfactory animal toxicity tests,there is still the possibility of unpredictable and sometimesvery serious toxic actions, and this is why I believe thatthere should still be one more safeguard before any drugis widely marketed. I think its initial use on a larger scalethan is possible during clinical trials should be kept undervery close supervision.

In the first paragraph of its editorial, The Chemist andDruggist states that The Lancet has cast a slur on themanufacturers of pharmaceutical specialities by its

criticism, and in the last paragraph it is so inconsiderateof the Cohen Committee as to suggest that a wider

knowledge of its classification of the therapeutic value ofnew drugs would be of no use to doctors. These com-ments

" tinged with emotion " are a manifestation of aconflict between the pharmaceutical industry, anxious tomarket drugs commercially, and the medical profession,anxious to use drugs, anxious to have new drugs developed,but increasingly anxious to use only drugs of real valueand to avoid the tragedy of iatrogenic disease caused bydrugs. The main concern of both the doctor and thepharmaceutical industry should be with the well-beingof our patients; if this demands a more cautious use ofnew drugs by doctors and has repercussions in thecommercial practices of the pharmaceutical industry,these changes must be accepted not castigated. Many of

the problems will require the greatest cooperation andgoodwill between doctors and the industry.

O. L. WADE.Department of Therapeutics and Pharmacology,Queen’s University of Belfast.

THE RISK OF AN OPERATION

SIR,-It was interesting to see from Mr. Skyrme Rees’sletter of March 17 that 86% of the so-called

" irreducibleminimum mortality of surgery " is due to pulmonaryembolism. If this is indeed so, then I feel that there is still

great hope of reducing the risk of an operation still furtherfor, from my own experience, I am utterly convinced thatpostoperative pulmonary embolism could soon be rele-gated to the limbo of forgotten things if only we couldeducate hospital staffs in the principles of venous return.

All my patients and those of many of my surgical friendshave the foot of their bed raised 9 in. postoperatively and, evenmore important, they are shown simple flexion and extensionmovements of the ankle which they carry out until they leavehospital. If they are shown these by the nursing staff, whobellow them into their ear as they recover from the anaesthetic,then they have no problem in remembering to carry them out.(I suppose one could fairly say that they are hypnotised.) Inthis way, venous blood is never allowed to lie fallow and

stagnate, the normal rapid venous return is maintained andthe risk of thrombosis eliminated.We should also wipe out this pernicious habit of pushing

patients out of bed on the first or second postoperative day sothat they can stagnate in an armchair. I personally have noobjection to early postoperative rising provided that the

patients are either able to walk (wearing well-fitting lace-upshoes instead of sloppy shambling slippers) or are encouragedto

" walk " while sitting in a chair by moving their ankles upand down every now and again as if beating time to music.

Provided we remember that venous return from thelower limbs is governed almost entirely by the calf-musclepump which, in turn, is operated by flexion and extensionmovements of the ankle, we have it within our power toabolish the bogy of pulmonary embolism, a subject whichhas provided material for papers and leading articles forfar too many years.

STANLEY RIVLIN.London, W.1.

SIR,-I was honoured to read in your columns ofMarch 24 a letter in answer to mine from Mr. McNeill

Love, whom I have greatly admired as a stimulating andperceptive teacher of surgery, to whom I owe a great dealin the past 32 years.

In considering whether raising the heels of a patientundergoing operation is an effective prophylactic measure,and indeed, if there is any prophylaxis to fatal pulmonaryembolus, I respectfully invite him to consider the follow-ing figures.The 6 patients mentioned in my letter of March 17 who died

from pulmonary embolism after appendicectomy were allunder 60: 1 was 23, 2 were in their 30s, and the others in their50s. There was no indication from the records whether theheels were raised.

In the five years 1944-48, of all the postmortem examinationsperformed at Dudley Road Hospital, Birmingham, 52 patientswere found to be dead of pulmonary embolism, yet only 17of these had been subject to operation. Of the remainder 34died in medical or surgical wards without ever lying on anoperating-table, and 1 had been brought to the hospital alreadydead.Of the total of 52 patients who died of pulmonary embolism,

18 were under 60 years of age-that is, 35%. Of the 17 whodied after operation, 6 (35%) were under 60. Of the 35 whodied without operation 14 (40%) were under 60. Of these 35,20 died in medical wards, and of these 20, 8 (40%,) were under