865

but important sections of the population were receiv-ing amounts of calcium, vitamin A, and riboflavinewell, below any acceptable physiological standard.These findings confirm the impression of the casualvisitor to Dublin. There he will find hotels andrestaurants in which those with money may buyunlimited quantities of the best, and richest foods.But outside he will find beggars in the streetswho look undernourished. How big are theunderfed and overfed minorities in Dublin and otherIrish cities is uncertain ; probably both are small.For -the majority the hard facts of pounds, shillings,and pence ensure a diet that is frugal but sufficient,and in most respects differs little in nutritional valuefrom the diets in England today. Tradition, however,still determines that all Irish families, whatevertheir economic status and both in town and country,eat more potatoes and less bread than correspondingfamilies in England. The Irish also eat little cheeseor fruit and are largely dependent on the potato forsupplies of vitamin C. ’

The four parts of the Nutrition Survey so far

published cover only the findings of the dietarysurveys. While these were in progress a widespreadclinical nutritional survey was also undertaken. Thisis now completed, but the data are not yet fullyanalysed, and until these clinical findings are publishedthe significance of the dietary surveys cannot be

finally appraised. Meanwhile we can congratulatethe Irish on planning and carrying out a large-scalenutritional survey on a sound statistical basis.

Probably no other country now possesses suchaccurate knowledge of what its people eat. When the

Snal reports are written up it is to be hoped that thoseresponsible for this excellent work will discard thecloak of anonymity which enshrouds the first four

parts.The Biology of Antibiotics

NOWADAYS, when penicillin has ceased to be a

wonder and streptomycin is beginning to be " last

year’s model," when even chloramphenicol and

’Aureomycin’ are losing their novelty though theyare not yet released for everyday use, and whenvaluable new antibiotics are reported every month ortwo, one is apt to regard the moulds and similarorganisms as convenient and highly efficient pharma-ceutical laboratories provided by a beneficent provi-dence to produce remedies for man’s worldly ills.And if we discard this anthropocentric view as toonaive, the question arises why do living organismsmanufacture this vast variety of complex compoundsapparently directed against a fairly limited range ofbacteria and other micro-organisms ? Analysing thematter further, it may be asked why Penicillia shouldbe so determined to eradicate gram-positive bacteria,whereas the Streptomycetes seem to be a particularlyvicious class ready to pounce on both gram-positiveand gram-negative micro-organisms, not to mentionvarious rickettsias and viruses. Within the narrowlimits of medicine these characteristics seem inexplic-able ; but when they are seen against the backgroundof general biology, as PRATT and DUFRENOY showin their book reviewed on p. 862, some of theseexplanations begin to appear.The component members of any society, whether

they are human beings or any other living organisms,

continuously influence, and are influenced by, theirenvironment. Further, the neighbouring beings ororganisms or cells constitute an important part ofthat environment. These principles are as true forthe growth of bacteria as for the waxing and waningof civilisations. The relations between differentorganisms living in the same space may be of variouskinds. Their influences on each other may be mutuallybeneficial, when the position is called symbiosis. Oneorganism may use the other to supply it with foodand protection against the outside world, as is doneby well-adapted parasites. Finally, one organism mayinhibit or altogether prevent the growth of another,presumably to gain more Lebensraum and food byeliminating its competitors ; this is the relationshipwhich VUILLEMIN, in 1889, called " antibiosis," fromwhich the modern term " antibiotic " is derived,though its sense is now narrowed to only part ofthis field. Such antibiosis is not restricted to bacteria.

Many higher plants possess means of keeping bacteriain check, and our own enzyme lysozyme is a similarprotective mechanism against bacteria. Some plantsexert an antibiotic action against other plants. -Thusin the sparsely vegetated Colorado deserts there is akind of daisy (encelia) which prevents the growth ofother plants in the neighbourhood by excreting atoxic substance (3-acetyl-6-methoxybenzaldehyde)which diffuses out from the centre.The apparently obliging behaviour of the moulds,

which labour to cure man’s ills, is an artefact producedby anthropocentrism and selection. Man pays particu-lar attention to the factors in his environment thatdo him harm or good. (Especially, a cynic would say,to those that do him harm.) Thus medical textbooksdescribe bacteriology in terms of the pathogenicmicro-organisms and hardly mention the much morenumerous non-pathogenic ones. In reality mostbacteria ignore man even more than he ignores them.,and the few micro-organisms that produce useful

therapeutic agents are a tiny minority among themillions that do not. Their apparently kind action ismerely one of a great variety of characters, whichhas been brought into prominence by man’s carefulselection of something which will be useful to him.The fineness of discrimination needed in this selectionmay be judged from WAKSMAN’S statement thatabout 10,000 cultures of organisms were studied inhis laboratory alone in the search for useful anti-

biotics ; about 1000 were found to have antibacterial

properties ; when these were grown in liquid mediaonly about 100 produced specific antibacterial sub-stances ; of these, 10 substances have been isolatedand described ; but only 1 has proved to be of

therapeutic importance-namely, streptomycin. Tobe of therapeutic value, an antibiotic substance mustbe highly poisonous to some pathogenic bacteria butnon-poisonous to the patient. Presumably such, asubstance is poisonous to an organism because itblocks some essential metabolic pathway. If it blocksa pathway common to all living cells, then it has awide range of action but it is toxic to the host andso useless. If it blocks a pathway which is irreplace-able only in a small group of bacteria, then thesubstance has a highly specific action, but it is of

therapeutic value only if this small group of bacteriahappens to contain important pathogens. All grada-tions between these extremes of antibiotic action

866

occur in nature, but it is only a special few in the middleof the range which have been selected by man formedical use..Why the Penicillia should be particularly antago-

nistic to gram-negative cocci, while Streptomycetesinhibit gram-negative ones, is still obscure. Furtherresearch may reveal some reason for this antagonismin the natural history of the Penicillia. It may be

just a case of overlapping, where a mechanism,devised by an organism for one purpose, happens toreact beneficially in quite a different biological systemelsewhere with which it could never have come intocontact by natural means. Thus the cinchona alkaloidsare used by man to destroy malaria parasites in hisblood ; yet the cinchona tree could never have comeinto biological contact with Plasmodia during its

evolutionary history, and it must have developed

Annotations

BLOOD DONORS

THE men and women whose blood is used for transfu-sions in increasing amounts year by year probably receivelittle thought except from those concerned with theirrecruitment and organisation, or when one of them hasthe rare misfortune to suffer temporary disablement andsues for compensation. That recourse to law shouldbe necessary to secure compensation is regrettable. In

proportion to the total number of donors who are bledeach year, the number who have to complain of theway in which they have been treated is very small,and very few of these have to seek financial compensationfor loss of wages or expenses incurred by-their temporarydisablement. In the case recently reported,! a donor’sarm had become infected. This complication may beunpleasant, causing inconvenience and perhaps anxiety ;but fortunately it is rare. In the years 1946-49 infectionof the site of venepuncture was reported to the regionaltransfusion centres on some 44 occasions. Duringthis period some 1,384,000 donors were bled by thesecentres, so the incidence of infection was about 1 in

31,450 donors bled. In 7 out of the 44 instances itseemed unlikely that the infection was attributable tothe venepuncture itself ; and, omitting these, theincidence of infection due to venepuncture was about1 in 37,000. There were probably further cases whichwere not reported to the centres ; but it may be inferredthat very few, or none, of these were serious.. Of the44 donors who did report, only 6, or 1 in 230,666, askedfor financial compensation ; and in each case this was

paid without recourse to law. In a smaller series ofsome 750,000 donors bled during the war years theincidence of infection of the site of venepuncture wasabout the same-namely, 1 in 31,500.The medical services and patients of this country

owe a considerable debt to their voluntary blood donors ;and, though these are repaid mainly by the satisfactionof knowing -that their gifts of blood have been used torelieve suffering, we cannot do less than ensure that thecare they get is of a high order. The responsibilitiesto the donor of, those who arrange the donor clinicsand take the blood are great. The apparent simplicityof this commonplace manoeuvre may tend after a

while to obscure the need for an immaculate techniquecarried out’by a skilled and practised operator. With’constant repetition, venepuncture becomes a dull occu-pation ; but it should riot be undertaken in a lightheartedor careless manner, and it should remain a medicalresponsibility. Nor should it be forgotten that thevoluntary blood donor deserves the best, medicallv and

1. Lancet, March 11, p. 461.

these alkaloids for some purpose or under some

stimulus of its own. Similarly morphine reacts on thehuman cerebral cortex so as to relieve pain, but thiscannot be the reason for its synthesis by the opiumpoppy. We must conclude that now and again abiological key happens to fit a biological lock quiteremote from the one for which it was primarilyshaped. Whether this applies to the selective actionof penicillin on staphylococci or of chloramphenicolon rickettsias can only be solved by further researchon the antibiotics. Work began in this field seventyyears ago with PASTEUR and JOUBERT,. but it is onlyin the past decade that it has been pursued withsystem, energy, and great resources. Progress, whichwas initially so slow, is now so fast that we mayreasonably expect to see these and many other

questions answered in the near future.

in other ways. This implies, among other things; a

polite and friendly atmosphere, a reasonable standardof comfort, and a competent operator who will not haveto " dig for victory " with each needle. Donors whohave been badly treated in any way do not come back,nor are they likely to persuade their friends to becomedonors. Should these volunteers be unlucky enough tosuffer injury or loss attributable to the donation ofblood, requests for compensation should be consideredsympathetically and rapidly.

OPINIONS FROM EASTBOURNE

THE Chancellor of the Exchequer has suggested thatthe proportion of the national income that can be devotedto health services has now reached its upper limit. TheCongress of the Royal Sanitary Institute, held inEastbourne from April 24 to 28, revealed lively concernthat available funds are not being used to the bestadvantage. Thus Earl de la Warr, in his inauguraladdress as president of the congress, spoke forcefullyabout the imbalance between expenditure on the curativeand on the preventive services. " Last year," he said,"

Exchequer and personal payments amounted to overJE450 million for the National Health scheme, and

during the same period the sum of E9 million was allowedfor subsidising new permanent houses, and just over

E6 million for the school health services. Clinics and

hospitals are great and wonderful institutions ... but ifwe had to choose between a hospital bed and having ahouse to ourselves, there is not much doubt where ourchoice would lie, on both personal and health grounds."Dr. H. C. Maurice Williams, president of the conference"of medical officers of health, spoke in similar vein." With a limit on national expenditure, a stage has beenreached when the relative values between an extensionof. the social services and the rehousing of the peopleought to be properly assessed. It appears illogical tohave reduced for financial reasons the erection of

permanent houses by 25% during the last two years,whilst the expenditure on other less essential socialwelfare is going ahead by leaps and bounds." Our

preoccupation with curative services was also criticisedby Prof. James Mackintosh, president of the preventive-medicine section. There had, he remarked, been nobroad conception of a national health policy, either inthe National Health Service Act or in the plans whichhad been put forward since the Act came into force."’On the contrary, there has been an unmistakabletendency to split the rounded concept of national healthinto artificial segments, each under a different govern-ment department. This creates a muddle of centralauthorities competing for the supervision of local healthservices at the very time when one might have hopedfor greater coordination and economy of effort.... At