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DIGITALIS AND VENOUS PRESSURE
1200 1948. Slight variations in technique may lead to misinterpretation, especially when judging progress by comparison with previous films, and the routine suggested in the revised report will be examined with interest by all radiologists. It has been assumed that before long most chest radiographs will be taken by X-ray tubes capable of carrying at least 400 milliamperes. When the maximum available output is less, it is better to reduce
the tube-film distance rather than increase the exposure time. The photo-electric timer, which automatically ends the exposure after a time appropriate to the size of the patient, is mentioned as a means of achieving more uniform radiographs. Those who have had the opportunity to examine a series of radiographs of the same patient taken by different radiographers with the aid of the phototimer will appreciate its value. Details of processing are included to re-emphasise the importance of great care in the darkroom. ACUTE RENAL FAILURE I ACUTE renal failure has been the subject of much debate in the past decade. There are several distinct types, which can be identified by the clinical history and pathologically. Once anuria has developed, however, the clinical course and the treatment are similar in all types. This similarity has led many workers to postulate for every type of acute renal failure a " unity of pathogenesis "-a unity either of the initiating disturbance in the kidney or of the morphological lesions which develop there, or of the functional disturbance which results from these lesions. The number of these unifying hypotheses is increasing. Some of the clearly defined explanations appear to apply to one type of renal failure but not to others. By contrast, other explanations apply to all but are so vague that they have little significance. types A refreshing paper on the pathogenesis of acute renal failure comes from Oliver et al.1 who have made a careful study of the kidney by microdissection-a very old technique which has been perfected and used with great success by Oliver in the investigation of other renal conditions. These workers distinguish two kinds of lesion involving the renal tubules, and offer an setiological explanation for each. The less common lesion is necrosis of tubular epithelium, confined to the proximal convoluted tubules and distributed evenly among all the nephrons. This necrosis is caused directly by tubular toxins which affect a specific part of the proximal tubule. The toxin is believed to act chemically on the epithelium ; but experimentally Schlegel’s technique revealed that it also greatly disturbed the blood-supply to the renal cortex. The second lesion, described as tubulorrhexis, was present in all clinical cases of acute renal failure. This lesion was originally identified histologically in the crush kidney by Dunn et a1.,2 and was recorded by Darmady3 who used the microdissection technique. Oliver’s account is more detailed and more fully documented than the earlier descriptions. The change consists in localised necrosis of tubular epithelium associated with disintegration of the basement membrane at the same point, so that the tubule is disrupted. The lesion occurs principally in the distal convoluted tubules or the collecting tubules, but is common also in the spiral segment. It can sometimes be found in other parts of the proximal convoluted tubule or in the loops of Henle, but is difficult to identify at these sites. It is always very irregular in its distribution among different nephrons; and Oliver and his colleagues interpret this irregularity as indicating that the tubulorrhexis must be produced by patchy ischaemia. This interpretation is, however, open to doubt. In man the kidneys did not show any of the other lesions which are accepted as characteristic stigmata of severe ischsemia. Furthermore, in dogs pure 1. Oliver, J., MacDowell, M., Tracy, A. J. clin. Invest. 1951, 30,
1305. 2. Dunn. J. S., Gillespie, M., Niven, J. S. F. Lancet, 3. Darmady, E. M. Brit. med. J. 1950, ii, 349.
1941, ii, 549.
renal ischaemia produced necrosis of proximal convoluted tubules but not localised tubulorrhexis. Oliver thus suggests that exactly the right degree of ischaemia must be applied to produce tubulorrhexis. It is difficult to accept that so delicately balanced a mechanism can account for a lesion found so very commonly in the kidneys of patients with anuria. The common type of tubulorrhexis affects the " lower nephron " and is invariably associated with casts in these segments. It can be reproduced experimentally in dogs with renal ischsemia followed by intravenous injection of haemoglobin, which produces casts in the lower seg. ments of the nephron. The casts are often above or below the site of the tubulorrhexis, rather than at it ; and Oliver believes that they do not cause the lesion. It must, however, be pointed out that in most of the clinical cases the patient had survived for nine to twelve days after the original damage to the kidney; and thus the condition of the affected tubule at the time of this damage can only be inferred. Secondly, those unversed in the technique will inevitably ask whether casts might not be moved along the tubule in the course of the dissection and disentangling of the individual nephrons with needles after the kidney has been macerated in concentrated hydrochloric acid for twelve to twenty-four hours. The possibility therefore remains that -the tubulorrhexis in the lower segments of the tubule may be a mechanical effect of casts in the lumen. Other problems are raised by this work. Oliver interprets the monocytic infiltration of the intermediate zone as a local reaction to tubulorrhexis of the spiral segments rather than as an indication of tubular leakage in the medulla. He maintains that tubulorrhectic lesions can heal only with great difficulty, either by the adhesion of connective-tissue fibres or by the irruption of granulation tissue. He believes that tubulorrhexis is important because the urine from the affected tubule escapes into the interstitial tissue or neighbouring vessels, instead of being excreted. Furthermore, it is suggested that the leakage of albuminous urine into the interstitial tissue produces aedema there, which impedes the flow of urine down the tubules of the region and compresses the
capillaries, producing further ischsemia. These ideas are all debatable, and there is that they will be widely discussed.
no
doubt
DIGITALIS AND VENOUS PRESSURE EXACTLY how digitalis works is still uncertain-though not for want of trying. It seems definitely to increase the contractile power of the heart, and, as Cushny1 showed over a quarter of a century ago, it causes arteriolar constriction. There is also a good deal of evidence that in normal animals its administration is followed by diminished cardiac output ; - but the reason for this is Dock and Tainter2 suggested that still disputed. the explanation lay in a constricting action on the hepatic veins which reduced the venous return to the heart ; but subsequent investigations have not consis. tently confirmed this observation. Tyrer3 has approached the problem afresh in a study of sheep in which the heart was replaced by a double. perfusion pump, thus excluding cardiac action on venous pressure. In four such sheep the addition of digoxin to the systemic venous reservoir was followed by a rise of pressure in the inferior vena cava. Since pulmonary and systemic circulations were perfused at a constant rate, total blood-flow through the venae cavae into the systemic venous reservoir was constant ; and the central venous pressure was fixed at zero. Tyrer suggests that the rise of venous pressure evoked by digoxin can be explained in three ways : (1) " a slight general venoconstriction along the length of the inferior vena cava, increasing slightly the gradient of pressure fall along this portion of the 1. Cushny, A. R. Digitalis and its Allies. London, 1925. 2. Dock, W., Tainter, M. L. J. clin. Invest. 1929, 8, 467. 3. Tyrer, J. H. Med. J. Aust. April 12, 1952, p. 496.
1201
system from the periphery"; (2) a localised sphincter-like venoconstriction of the upper part of the inferior vena cava ; or (3) a selective action by the digoxin, causing a diminished blood-flow along the superior vena cava and an increased blood-flow along the inferior vena cava. Tyrer regards this third possibility and he concludes that the evidence of a as unlikely ; peripheral action of digoxin on venous pressure is unequivocal. On the other hand, this " is not to suggest that the principal action of digoxin in intact sheep is on Indeed Tyrer describes experiments venous pressure." in four control sheep with intact circulations in which the intravenous injection of digoxin caused either no alteration or a slight fall of mean right atrial pressure. This fresh evidence from Australia strongly supports the hypothesis that digitalis has a primary action on venous pressure, and it will be interesting to see whether other investigators can confirm these observations. venous
PERCUSSION
Leopold Auenbrugger (1722-1809), the son of an Austrian innkeeper, and in his youth a picturesque tapper of wine-barrels, later gained eminence as a physician by his ability to apply his powers of careful observation and percussion ; but his Inventum Novum (1761), like many good discoveries, lay unnoticed for fifty years until Napoleon’s physician, Courvoisart, translated it into French. Though some now regard percussion lightly, others hold it so useful that they practise it not only on the chest but also on the head, abdomen, and joints ; and at least one eminent teacher draws attention to the " dull sound of an absent knee-jerk." There is no doubt that, as a means of comparing the resilience of one part of the body-surface with another, percussion valuable art. One of the difficulties with percussion is in trying to remember the absolute quality of a sound; and the most successful exponents limit their observations to a comparison of sounds from adjacent points, or from corresponding points on the two sides of the body. Burger et al.l have gone some way towards defining how percussion is done ; but what factors determine the quality of a percussion-note, and why do the underlying structures of the body influence the character of a sound radiated when the surface is struck1 The sound that reaches the ear is radiated from the body-surface ; each minute area of surface disturbs the air in its immediate neighbourhood, and the disturbance is transmitted to the ear with the velocity’ of sound in air. The ear summates the multitude of small components into a whole " sound," movements of air particles in one direction cancelling out those that arrive at the ear simultaneously with an opposite movement. Thus the two sides of a vibrating sheet produce opposite effects, and if the distance to the ear from opposite sides is the same no sound is heard however violently the sheet is shaken. One has only to percuss one’s finger lightly in space, or shake a small fragment of For this reason loudpaper, to demonstrate this. speakers need a baffle. Every sound can be regarded as the sum of a number of pure tones. The note middle C has a frequency of 256 cycles per second, and in the time of one complete oscillation sound travels about 50 inches. Thus for this frequency of vibration to cause a maximum sound, the vibrating surface must be of such a size that the sound-path difference from the two surfaces to the ear is about 25 inches. Some is
a
sound will be
heard, however, if the path-difference is
less-say, greater
than 5 inches.
High
notes
are
readily
radiated from small surfaces, but low notes require a
When a
surface or baffle area. well-ventilated part of the chest is area of the surface is momentarily
large vibrating large
a
1. Burger, H. C., Casteleyn, G., Jordan, F. L. J. 1952, 142, 108.
percussed depressed
Acta med. scand.
and vibrates as a whole ; a relatively low note is produced and dies away at a speed depending on the viscosity of the skin and adjacent structures, of which the pleximeter finger is a small part. When fluid or a structure such as the liver underlies the surface, the part, although equally elastic, is less compressible. The surface is not depressed as a whole ; but the part under the struck finger is depressed while the surround. ing tissue rises at the sides of the finger and a wave spreads over the surface with the velocity of sound in tissue, just as a pond surface is disturbed by a falling stone. Such a surface gives a higher-pitched sound, and the more complex wave pattern gives rise to a higher rate of damping, with the characteristic dull sound. Echoes from internal surfaces or cavities are sometimes said to contribute to the quality of the sound. Possibly a large air cavity near the surface may resonate and produce surface ripples ; and this may account for the high-pitched, undamped, resonant quality known as tympanic which is elicited over an empty stomach or a
pneumothorax. Sound echoes of
frequencies beyond the range of megacycles per second-can be elicited from internal body structures, in the same way as the ocean bed is depth-sounded by sound pulses from piezoelectric or magneto-striction radiators. The echoes are amplified and presented on a radar-type cathoderay screen. Flaws in machinery and other industrial products are commonly located in this way ;and work now proceeding in this country shows that in the body gross changes in internal density or elasticity can be detected similarly, though the waves do not go beyond an air interface. Such a procedure will determine the thickness of tissue overlying bone, show some defects in bones, and enable some structures, such as the liver and heart and pleural effusions, to be outlined.
hearing-e.g.,
2
THE BIRTHDAY HONOURS
THOSE who value tradition in such matters will be happy to see that a baronetcy has been conferred on Sir Cecil Wakeley, as on so many of his forerunners in the presidency of the Royal College of Surgeons. Since his first election in July, 1949, Sir Cecil has both exemplified and reinforced the vitality of his college, and the honour he has so well deserved will give all the more pleasure because Lady Wakeley and his son are also members of our profession. Mr. Walter Elliot, who must have been disclaiming other titles since the ’20s, becomes a Companion of Honour, a designation earned alike by his public work and personal distinction. As is similarly appropriate, Lieut-General Sir Neil Cantlie is promoted K.C.B. in recognition of his notable work as directorgeneral of medical services. The knighthood for Prof. W. E. Hume sets the seal on a valuable and distinguished career which included service in France as a consulting physician to the Army in the first world war, the chair of medicine at Newcastle, and the offices of senior censor and Harveian orator in the Royal College of Physicians. Group-Captain H. R. G. Poate, who is also created a knight, was president of the Royal Australasian College of Surgeons from 1945 to 1947, and Dr. Edgar Laurent is a member of the Executive and Legislative Councils of The names of other doctors appearing in Mauritius. the Birthday Honours are set out on p. 1205, and they form an impressive group. Outside the confines of medicine we are glad to note that Mr. J. M. K. Hawton, secretary to the Ministry of Health, is created K.C.B., in somewhat tardy recognition of his important contribution to the planning of the health service. Prof. R. A. Fisher, F.R.S., the eminent geneticist and statistician, and Mr. B. H. C. Matthews, F.R.S., the new professor of physiology at Cambridge, are among the new knights, and Miss Mabel Liddiard, retiring president of the Royal College of Midwives, is appointed c.B.E.
the tube-film distance rather than increase the exposure time. The photo-electric timer, which automatically ends the exposure after a time appropriate to the size of the patient, is mentioned as a means of achieving more uniform radiographs. Those who have had the opportunity to examine a series of radiographs of the same patient taken by different radiographers with the aid of the phototimer will appreciate its value. Details of processing are included to re-emphasise the importance of great care in the darkroom. ACUTE RENAL FAILURE I ACUTE renal failure has been the subject of much debate in the past decade. There are several distinct types, which can be identified by the clinical history and pathologically. Once anuria has developed, however, the clinical course and the treatment are similar in all types. This similarity has led many workers to postulate for every type of acute renal failure a " unity of pathogenesis "-a unity either of the initiating disturbance in the kidney or of the morphological lesions which develop there, or of the functional disturbance which results from these lesions. The number of these unifying hypotheses is increasing. Some of the clearly defined explanations appear to apply to one type of renal failure but not to others. By contrast, other explanations apply to all but are so vague that they have little significance. types A refreshing paper on the pathogenesis of acute renal failure comes from Oliver et al.1 who have made a careful study of the kidney by microdissection-a very old technique which has been perfected and used with great success by Oliver in the investigation of other renal conditions. These workers distinguish two kinds of lesion involving the renal tubules, and offer an setiological explanation for each. The less common lesion is necrosis of tubular epithelium, confined to the proximal convoluted tubules and distributed evenly among all the nephrons. This necrosis is caused directly by tubular toxins which affect a specific part of the proximal tubule. The toxin is believed to act chemically on the epithelium ; but experimentally Schlegel’s technique revealed that it also greatly disturbed the blood-supply to the renal cortex. The second lesion, described as tubulorrhexis, was present in all clinical cases of acute renal failure. This lesion was originally identified histologically in the crush kidney by Dunn et a1.,2 and was recorded by Darmady3 who used the microdissection technique. Oliver’s account is more detailed and more fully documented than the earlier descriptions. The change consists in localised necrosis of tubular epithelium associated with disintegration of the basement membrane at the same point, so that the tubule is disrupted. The lesion occurs principally in the distal convoluted tubules or the collecting tubules, but is common also in the spiral segment. It can sometimes be found in other parts of the proximal convoluted tubule or in the loops of Henle, but is difficult to identify at these sites. It is always very irregular in its distribution among different nephrons; and Oliver and his colleagues interpret this irregularity as indicating that the tubulorrhexis must be produced by patchy ischaemia. This interpretation is, however, open to doubt. In man the kidneys did not show any of the other lesions which are accepted as characteristic stigmata of severe ischsemia. Furthermore, in dogs pure 1. Oliver, J., MacDowell, M., Tracy, A. J. clin. Invest. 1951, 30,
1305. 2. Dunn. J. S., Gillespie, M., Niven, J. S. F. Lancet, 3. Darmady, E. M. Brit. med. J. 1950, ii, 349.
1941, ii, 549.
renal ischaemia produced necrosis of proximal convoluted tubules but not localised tubulorrhexis. Oliver thus suggests that exactly the right degree of ischaemia must be applied to produce tubulorrhexis. It is difficult to accept that so delicately balanced a mechanism can account for a lesion found so very commonly in the kidneys of patients with anuria. The common type of tubulorrhexis affects the " lower nephron " and is invariably associated with casts in these segments. It can be reproduced experimentally in dogs with renal ischsemia followed by intravenous injection of haemoglobin, which produces casts in the lower seg. ments of the nephron. The casts are often above or below the site of the tubulorrhexis, rather than at it ; and Oliver believes that they do not cause the lesion. It must, however, be pointed out that in most of the clinical cases the patient had survived for nine to twelve days after the original damage to the kidney; and thus the condition of the affected tubule at the time of this damage can only be inferred. Secondly, those unversed in the technique will inevitably ask whether casts might not be moved along the tubule in the course of the dissection and disentangling of the individual nephrons with needles after the kidney has been macerated in concentrated hydrochloric acid for twelve to twenty-four hours. The possibility therefore remains that -the tubulorrhexis in the lower segments of the tubule may be a mechanical effect of casts in the lumen. Other problems are raised by this work. Oliver interprets the monocytic infiltration of the intermediate zone as a local reaction to tubulorrhexis of the spiral segments rather than as an indication of tubular leakage in the medulla. He maintains that tubulorrhectic lesions can heal only with great difficulty, either by the adhesion of connective-tissue fibres or by the irruption of granulation tissue. He believes that tubulorrhexis is important because the urine from the affected tubule escapes into the interstitial tissue or neighbouring vessels, instead of being excreted. Furthermore, it is suggested that the leakage of albuminous urine into the interstitial tissue produces aedema there, which impedes the flow of urine down the tubules of the region and compresses the
capillaries, producing further ischsemia. These ideas are all debatable, and there is that they will be widely discussed.
no
doubt
DIGITALIS AND VENOUS PRESSURE EXACTLY how digitalis works is still uncertain-though not for want of trying. It seems definitely to increase the contractile power of the heart, and, as Cushny1 showed over a quarter of a century ago, it causes arteriolar constriction. There is also a good deal of evidence that in normal animals its administration is followed by diminished cardiac output ; - but the reason for this is Dock and Tainter2 suggested that still disputed. the explanation lay in a constricting action on the hepatic veins which reduced the venous return to the heart ; but subsequent investigations have not consis. tently confirmed this observation. Tyrer3 has approached the problem afresh in a study of sheep in which the heart was replaced by a double. perfusion pump, thus excluding cardiac action on venous pressure. In four such sheep the addition of digoxin to the systemic venous reservoir was followed by a rise of pressure in the inferior vena cava. Since pulmonary and systemic circulations were perfused at a constant rate, total blood-flow through the venae cavae into the systemic venous reservoir was constant ; and the central venous pressure was fixed at zero. Tyrer suggests that the rise of venous pressure evoked by digoxin can be explained in three ways : (1) " a slight general venoconstriction along the length of the inferior vena cava, increasing slightly the gradient of pressure fall along this portion of the 1. Cushny, A. R. Digitalis and its Allies. London, 1925. 2. Dock, W., Tainter, M. L. J. clin. Invest. 1929, 8, 467. 3. Tyrer, J. H. Med. J. Aust. April 12, 1952, p. 496.
1201
system from the periphery"; (2) a localised sphincter-like venoconstriction of the upper part of the inferior vena cava ; or (3) a selective action by the digoxin, causing a diminished blood-flow along the superior vena cava and an increased blood-flow along the inferior vena cava. Tyrer regards this third possibility and he concludes that the evidence of a as unlikely ; peripheral action of digoxin on venous pressure is unequivocal. On the other hand, this " is not to suggest that the principal action of digoxin in intact sheep is on Indeed Tyrer describes experiments venous pressure." in four control sheep with intact circulations in which the intravenous injection of digoxin caused either no alteration or a slight fall of mean right atrial pressure. This fresh evidence from Australia strongly supports the hypothesis that digitalis has a primary action on venous pressure, and it will be interesting to see whether other investigators can confirm these observations. venous
PERCUSSION
Leopold Auenbrugger (1722-1809), the son of an Austrian innkeeper, and in his youth a picturesque tapper of wine-barrels, later gained eminence as a physician by his ability to apply his powers of careful observation and percussion ; but his Inventum Novum (1761), like many good discoveries, lay unnoticed for fifty years until Napoleon’s physician, Courvoisart, translated it into French. Though some now regard percussion lightly, others hold it so useful that they practise it not only on the chest but also on the head, abdomen, and joints ; and at least one eminent teacher draws attention to the " dull sound of an absent knee-jerk." There is no doubt that, as a means of comparing the resilience of one part of the body-surface with another, percussion valuable art. One of the difficulties with percussion is in trying to remember the absolute quality of a sound; and the most successful exponents limit their observations to a comparison of sounds from adjacent points, or from corresponding points on the two sides of the body. Burger et al.l have gone some way towards defining how percussion is done ; but what factors determine the quality of a percussion-note, and why do the underlying structures of the body influence the character of a sound radiated when the surface is struck1 The sound that reaches the ear is radiated from the body-surface ; each minute area of surface disturbs the air in its immediate neighbourhood, and the disturbance is transmitted to the ear with the velocity’ of sound in air. The ear summates the multitude of small components into a whole " sound," movements of air particles in one direction cancelling out those that arrive at the ear simultaneously with an opposite movement. Thus the two sides of a vibrating sheet produce opposite effects, and if the distance to the ear from opposite sides is the same no sound is heard however violently the sheet is shaken. One has only to percuss one’s finger lightly in space, or shake a small fragment of For this reason loudpaper, to demonstrate this. speakers need a baffle. Every sound can be regarded as the sum of a number of pure tones. The note middle C has a frequency of 256 cycles per second, and in the time of one complete oscillation sound travels about 50 inches. Thus for this frequency of vibration to cause a maximum sound, the vibrating surface must be of such a size that the sound-path difference from the two surfaces to the ear is about 25 inches. Some is
a
sound will be
heard, however, if the path-difference is
less-say, greater
than 5 inches.
High
notes
are
readily
radiated from small surfaces, but low notes require a
When a
surface or baffle area. well-ventilated part of the chest is area of the surface is momentarily
large vibrating large
a
1. Burger, H. C., Casteleyn, G., Jordan, F. L. J. 1952, 142, 108.
percussed depressed
Acta med. scand.
and vibrates as a whole ; a relatively low note is produced and dies away at a speed depending on the viscosity of the skin and adjacent structures, of which the pleximeter finger is a small part. When fluid or a structure such as the liver underlies the surface, the part, although equally elastic, is less compressible. The surface is not depressed as a whole ; but the part under the struck finger is depressed while the surround. ing tissue rises at the sides of the finger and a wave spreads over the surface with the velocity of sound in tissue, just as a pond surface is disturbed by a falling stone. Such a surface gives a higher-pitched sound, and the more complex wave pattern gives rise to a higher rate of damping, with the characteristic dull sound. Echoes from internal surfaces or cavities are sometimes said to contribute to the quality of the sound. Possibly a large air cavity near the surface may resonate and produce surface ripples ; and this may account for the high-pitched, undamped, resonant quality known as tympanic which is elicited over an empty stomach or a
pneumothorax. Sound echoes of
frequencies beyond the range of megacycles per second-can be elicited from internal body structures, in the same way as the ocean bed is depth-sounded by sound pulses from piezoelectric or magneto-striction radiators. The echoes are amplified and presented on a radar-type cathoderay screen. Flaws in machinery and other industrial products are commonly located in this way ;and work now proceeding in this country shows that in the body gross changes in internal density or elasticity can be detected similarly, though the waves do not go beyond an air interface. Such a procedure will determine the thickness of tissue overlying bone, show some defects in bones, and enable some structures, such as the liver and heart and pleural effusions, to be outlined.
hearing-e.g.,
2
THE BIRTHDAY HONOURS
THOSE who value tradition in such matters will be happy to see that a baronetcy has been conferred on Sir Cecil Wakeley, as on so many of his forerunners in the presidency of the Royal College of Surgeons. Since his first election in July, 1949, Sir Cecil has both exemplified and reinforced the vitality of his college, and the honour he has so well deserved will give all the more pleasure because Lady Wakeley and his son are also members of our profession. Mr. Walter Elliot, who must have been disclaiming other titles since the ’20s, becomes a Companion of Honour, a designation earned alike by his public work and personal distinction. As is similarly appropriate, Lieut-General Sir Neil Cantlie is promoted K.C.B. in recognition of his notable work as directorgeneral of medical services. The knighthood for Prof. W. E. Hume sets the seal on a valuable and distinguished career which included service in France as a consulting physician to the Army in the first world war, the chair of medicine at Newcastle, and the offices of senior censor and Harveian orator in the Royal College of Physicians. Group-Captain H. R. G. Poate, who is also created a knight, was president of the Royal Australasian College of Surgeons from 1945 to 1947, and Dr. Edgar Laurent is a member of the Executive and Legislative Councils of The names of other doctors appearing in Mauritius. the Birthday Honours are set out on p. 1205, and they form an impressive group. Outside the confines of medicine we are glad to note that Mr. J. M. K. Hawton, secretary to the Ministry of Health, is created K.C.B., in somewhat tardy recognition of his important contribution to the planning of the health service. Prof. R. A. Fisher, F.R.S., the eminent geneticist and statistician, and Mr. B. H. C. Matthews, F.R.S., the new professor of physiology at Cambridge, are among the new knights, and Miss Mabel Liddiard, retiring president of the Royal College of Midwives, is appointed c.B.E.