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been made in the campaign against venereal disease.The benefit to the coming generations would itself
justify the Minister of Health in testing medical opinionon the point.
CLOSE-UP OF SPERMATOZOA
THE electron microscope, which gives effective magni- JL
fications of 50,000 or more diameters, and has alreadytold us much about bacterial appearances under electronbombardment, has lately been turned on the sperma- E
tozoon in the hope of resolving some of the outstanding (doubts about its structure. In this apparatus magnetic- ]field " lenses " replace the glass ones of compound 1
microscopes and differentiation depends on differences in J
density within the specimen rather than on variation inrefractive indices or colour. The conditions for examin-
ing specimens by electron microscopy are importantbecause the vacuum, the drying of the specimen or eventhe electron bombardment itself may cause artefacts 1
which can masquerade as normal structure. It seems, <
however, that Seymour and Benmosche 1 have seen more i
clearly than hitherto a normal human spermatozoon <<and their pictures-three are needed to include a single sperm-have, at 13,500 and 27,000 diameters, clear-cut definition. At these magnifications the pear-shaped <<head of the human sperm has a crater-like notch on the <<vertex and within it a structure less opaque than therest of the head. The body of the spermatozoon, which (
when seen by refractive microscope was called the neck, :
is segmented, having 9-12 segments in the specimens ]examined. Throughout the length of the body runs acore, uniform in diameter and denser than the surround- 1ing segments, and it is this core which becomes the tail. 1The tail does not end abruptly but breaks up into ablurred smudge and it is much longer than has pre-viously been described. The belief that the body of thesperm contains a skein formation was not confirmed butthe segmentation probably explains the extraordinarymotility qf the head as it is propelled forwards. Withmotion pictures Seymour and Benmosche watched thehead of a spermatozoon penetrating the ovum in thefirst stage of fertilisation and they speculate on thepossibility of the notch on the vertex containing somesort of suction apparatus which helps penetration.
EXTRA MILK
THE medical certificate required under the Sale ofMilk (Restriction) Order, 1941, has come in for somecriticism, and the Ministry of Food is discussing possible alternatives with the B.M.A. Extra milk, up to a limit
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of 2 pints a day, may only be recommended if the patientis suffering from (a) active tuberculosis ; (b) silicosis ; ,
(c) conditions in which the patient is unable to swallowsolids by reason of an affection of the mouth, throat or ]gullet ; (d) gastric, duodenal or anastomotic ulcer ; (e) :illnesses characterised by high and prolonged fever ; or
(f) the results of a major operation. This list was drawnup by the special diets committee of the M.R.C. andmust cover the majority of indications. It is question-able, however, whether the doctor should not have beenleft free to consider each case on its merits. On theother hand, it is an unenviable task to refuse milk tQ anypatient, and the doctor may sometimes be glad of suchdefinite grounds for refusal. The certificate when com-
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pleted is handed by the householder direct to the milk-man. This is intended to simplify and hasten procedure,but many patients will object to their disabilities beingthus revealed to tradespeople. It would surely besufficient if the doctor stated that the patient wassuffering from one 01 the conditions on the prescribed listwithout specifying which. Members of the nationalmilk scheme, children receiving milk in schools, andpatients in hospitals and nursing-homes are excluded1. Seymour, F. I., and Benmosche, M. J. Amer. med. Ass. 1941,
116, 2489.
from the restrictions, and other people who are accus-tomed to drink a lot of milk will automaticallv have alarge ration, since this is calculated as six-sevenths ofthe previous consumption. The number of cases whichcannot be met by a little readjustment within the house-hold is therefore likely to be small.
Colonel (temporary Brigadier) ALEXANDER HOODsucceeds Lieut.-General Sir William MacArthur as
director-general of the Army Medical Services on Aug. 1.Brigadier Hood graduated from the University of
Edinburgh in 1910 and received a commission in theR.A.M.C. two years later.
SYSTOLIC MURMURS
IN his Honyman-Gillespie lecture in Edinburgh lastweek Prof. D. M. Lyon said that up to the end of lastcentury any cardiac murmur was usually taken toindicate heart disease. Then began a swing in theopposite direction and the study and significance ofmurmurs became derided. He believed that a balancewas necessary. Murmurs were produced when turbulencewas introduced into the blood-flow. This could becaused by changes in the speed of flow, or the viscosityof the fluid, and by constriction of the channel. Mereroughening of the surface of the channel did not produceeddying. Mitral systolic organic murmurs varied fromsoft gentle blowing sounds to loud rasping sounds accord-ing to the state of activity of the heart muscle. Themurmur of dilatation was softer and not so well propagated.Tricuspid systolic organic murmurs were relatively rare ;they were of higher pitch than mitral murmurs andpoorly propagated. In view of the reputation of thetricuspid valve as an escape valve it was surprising thattricuspid murmurs were heard so seldom. At theaortic valve organic narrowing was relatively rare andmost systolic murmurs were due to dilatation of theaorta along with thickening of the valve, especially theslight projection of a fibrous or calcified cusp. Pul-monary systolic murmurs were still rarer and most werecongenital. Functional murmurs were always systolicexcept for the murmur of pulmonary incompetencesometimes found in conditions of raised pulmonaryblood-pressure. They were mostly feeble and poorlyconducted. They were probably found in 3% of allrecruits and in 80% of athletes after severe exercise.In children various reports put the incidence at between10 and 60%. The cardio-respiratory murmur was heardalong the left border of the heart and beyond ; lessfrequently over the right side. It often occurred inhealthy persons. In quality it resembled interruptedbreath sounds of which it was really an accentuation.An interrupted puffing or whiffing sound was presentduring the whole of inspiration and might extend intoexpiration. It was usually heard best with the subjectin the upright position and stopped if he held his breath.Exercise increased its intensity which, however, wasvery variable at different examinations. Haemic mur-
murs were caused by turbulence due to decreasedviscosity of the blood ; they w re heard at both base andapex but the mechanism must be different-turbulenceof the flow at the aortic and pulmonary valves anddilatation of the mitral valve. Hsemic murmurs shouldnot be diagnosed in the absence of severe anaemia.When the heart was over-active or too rapid functionalmurmurs might be heard at the apex. These werecommon during excitement and in " soldier’s heart." Athrill might be palpable and the first sound appearrough. These features disappeared when the heart-ratefell and must not be taken as indicating mitral stenosis.The murmurs of hyperthyroidism and fever were of thesame nature. Pulmonary functional systolic murmurswere mostly faint and poorly conducted and were largelydue to slight variations in shape or deformity of thepulmonary vessels; that was apart from cardio-respiratoryand hsemic murmurs. - They were found largely inchildren and young people with plastic chest walls, andmight be produced by pressure of the stethoscope. Itwas important to remember the subclavian murmurheard beneath the clavicle when the arm was raised.
