709

and steepness of the Qs wave, from infarcts where therewas both clinical and histological evidence of some

muscle activity. Seeking another explanation, Prinzmetaland his associates recorded direct electrocardiogramsfrom parts of the ventricle which had been progressivelydamaged by burning or excision. When only subepi-cardial muscle was damaged R waves were still recorded,but when the outer third of the ventricular wall or the

deeper areas were involved R waves were replaced byQs waves. These observations suggested that the sub-endocardial muscle, probably because of its rapiddepolarisation, contributes nothing to the R wave in anepicardial lead, and that Qs leads can be produced bysubepicardial as well as by transmural infarction. Prinz-inetal and also Grant and Murray confirm the practicaldiagnostic importance of Qs waves and Q waves of 0-04sec. as signs of infarction, but seem to contradict eachother on the theoretical aspect. The difference may be

explained by the use of direct leads by Prinzmetal andof body-surface leads by Grant and Murray. This workhelps to explain some of the limitations of cardiographicdiagnosis.

1. See Lancet, 1946, ii, 871 ; Ibid, 1948, ii, 860 ; Ibid, 1949, i,1013 ; Ibid, 1952, i, 88.

2. Leifson, E., Carhart, S. R., Fulton, McD. J. Bact. 1955, 69, 73.3. Pijper, A. Nature, Lond. 1955, 175, 214.

THE GREAT SCHISMFOR some years microbiological circles have been

stirred by a debate, on the function of the bacterial

flagellum, between Prof. A. Pijper on the one side andalmost all the world on the other.! This heretic believesthat, far from being the organ of locomotion, the

flagellum is a trailing appendage of an automotive cell ;and his evidence is formidable. Oddly enough, throughoutthe argument little attention has been paid to thedetailed structure of flagella, apart from some picturesfrom the electron microscope which are more elegantthat informative. Now Leifson and his colleagues 2have shown that in stained preparations the flagellaof proteus have in the main two distinct and well-defined shapes. What they call " normal" is an openspiral (or zigzag) of two to three waves : " curly"is a tighter spiral (or zigzag) of four to six waves. Thetwo may be found on different flagella of the samebacterium, and there are two rarer types. Which typei. seen is influenced to some extent by the environmentin which the bacterium has grown. The wave-lengthsof each type of curve are remarkably constant for thesame species of bacterium. Almost simultaneouslyPijper has published a note on the same subject,based, as always, on observation of the living bacillusilluminated on the dark field by sunlight. He confirmshis original statement that as a general rule the bacteriumadvances by a spiral movement of its body with theflagellum sticking straight out behind, like an otter’srudder. (In the photographs this always seems a bitfuzzy.) Under circumstances which he has not yetdefined, this straight tail shortens and assumes a spiralshape which may have one of two wave-lengths, onetwice as long as the other. Initially the change is

reversible, but in the end the organ always finishes asa helix or splits into fine helicules. These may whirlabout for a short time and thereby give some erraticmovement to the bacterium (quite distinct in Pijper’sview from true motility), but their development isassociated with stiffening of the body and final immobility.A cautious view suggests that these two reports

describe the same phenomena modified by differencesin method. If the development of Pijper’s helicules isalways associated with death, or at any rate immobility,it is not surprising that they should be the structuresseen in stained preparations. He says that they mayappear to move to any part of the cell wall, which wouldexplain the lophotrichous and peritrichous arrangementsso loved by the systematists. What he does not mentionis whether these helicules retain the wave-length of thehelix from which they derive. Leifson has carefully

measured the wave-lengths of his two forms of curve,but does not call attention to what is clear from his

figures-that the wave-length of " normal" curves is

always about twice that of " curly." In comparingresults obtained by methods so different it would beunfair to ask for complete agreement, but it is a fairguess that Leifson’s flagella are Pijper’s helicules. Isthe fuzziness of Pijper’s rod-like flagellum due to its

being made up of a sheaf of flagellella And is this thebeginning of the end of the great schism ?

1. Magill, T. P. J. Immunol. 1955, 74, 1.2. Mon. Bull. Min Hlth Lab. Serv. 1955, 14, 34.

THE EVIL SPIRITS

MANY distinguished bacteriologists and immunologistshave talked optimistically of the problem of infectiousdiseases as virtually solved ; and in his presidentialaddress to the American Association of Immunologists,lDr. T. P. Magill has taken these people to task.

Like Dubos, whose latest book is reviewed on p.704, hedraws attention to our anthropomorphic attitude of mind.He points out that the peaceful bacterium, trying to findfood and shelter in man, is termed an aggressor, whereasit is just as reasonable to call man the aggressor ; andthat many of the manifestations of disease arise onlywhen man tries to exorcise these supposedly evil spirits.This viewpoint has virtues, not the least of which is itsrecognition that the aim of preventive medicine shouldbe less to eliminate an infection than to attempt to cometo terms with it. Attempts at elimination may have beenless strikingly successful than the decline in mortality-rates suggests. It is galling to have to admit that therates for tuberculosis, diphtheria, measles, and pneu-monia began to fall long before modern preventivemeasures could have taken effect. A factor that is often

neglected in calculations on trends of an infectious diseaseis its natural history or ecology. There are many examplesof diseases which have ravaged populations until in thecourse of time they have lost their malignant character.Such a change may be due to any of several causes.Huge numbers of susceptible people may havedied, leaving a resistant core ; and in the microbial

population it is the less virulent organisms whose survivalis favoured, since the organisms which kill their hosthave entered a blind alley. The recent myxomatosisepizootics in Australia and in this country have shownsuch processes. There are likewise examples of diseasesregaining their former severity.

Magill’s lecture will have failed in its purpose if it

encourages any ideas of nihilism : public-health measures,immunisation, and antitoxin therapy are indispensable.The lesson to be lea,rnt is that infectious diseases are farfrom conquered and that present methods of controllingthem are far from perfect. In our pride at how muchknowledge of bacteriology and immunology has beengained, we must beware of becoming too complacentabout the evil spirits.

FOOD-POISONINGTHE Public Health Laboratory Service has published

another of its valuable annual reports on food-poisoningin England and Wales. This report, on the year 1953,2contains an immense amount of data, much of which isgiven in tables ; and it lacks the dramatic impact of thesame facts described in narrative form. In 1953 therewere 5277 incidents-an increase of 1758 over the

previous year. These incidents consisted of outbreaks,family outbreaks, and sporadic cases. The increase isreflected in all the causes listed-namely staphylococci,Clostridium welchii, undiscovered, and particularlysalmonella. Better reporting must be taken into account,but by the most optimistic estimate there has been nodecrease in food-poisoning. The authors of this reportbelieve that at least 4000 cases were not notified-whichis a very high proportion.As in previous years meat dishes, particularly processed

or made-up meat dishes, were the most important vehicle ;