562

"came several years after that of the influenza wave.He points out also that clinical cases of encephalitiswere absent from the records of the pandemic ofinfluenza of 1889-92. As to aetiology cerebro-spinalfever is due to the meningococcus, and the researches,,of Dr. Flexner and his collaborators at the RockefellerInstitute have demonstrated that poliomyelitis is dueto a filter-passing virus. Epidemic encephalitis isprobably due to a similar virus. Dr. Flexner reviewsthe work on the herpes virus and concludes that it isunlikely that simple herpes and epidemic encephalitishave a common aetiology. Accumulated evidenceindicates that all these nervous epidemics are man-borne infections spread chiefly by way of the respira-tory tract. Dr. Flexner expresses no definite opinionon post-vaccinal encephalitis, holding that its exact.aetiology is still obscure.

PURER RIVERS.

THE first report of the Joint Advisory Committee onRiver Pollution is a businesslike and unanimousdocument. The law, it seems, is not inadequate toprevent contamination, but the law is not enforced.Serious and avoidable pollution exists, says the.Committee, partly because the jurisdiction of thevarious administrative authorities is confined to aparticular area only, partly because the bodies which.ought to enforce the law have a number of other morepressing duties to discharge, and partly because thegame-keepers are also poachers. The prevention ofpollution should be in the hands of an authority.exercising jurisdiction over the river as a whole(including its tributaries) at any rate so far as non-tidal waters are concerned. The creation of riversboards or joint committees for this purpose isalready possible under the existing law. Under,Section 14 of the Local Government Act of 1888, theMinistry of Health can set up such bodies by ProvisionalOrder on the application of the county councils andcounty borough councils concerned. The reportrecommends that this existing provision be speciallybrought to the notice of all these councils. There isreason to believe that the necessary applications tothe Ministry of Health would then in many cases bemade, and an important step would have been takentowards the ideal of purer rivers. The rivers Thamesand Lee are controlled by special statutory ConservancyBoards with which the report does not propose tointerfere. The powers of these two bodies, so vitalto the water-supply of the metropolis, are alreadygreater than the ordinary powers given by the RiverPollution Acts. Indeed the methods employed bythe Metropolitan Water Board for treating Thameswater have, both in respect of finance and purification,been so successful as to encourage recourse to riverwater for domestic supply, and have been officially- praised in the recent annual report of the Ministry.of Health. Elsewhere, it is recommended, the RiversBoard areas should be big enough to make sure thatskilled officers can be employed, and not so big asto make it impossible for the chief officers to keepthemselves thoroughly informed of the existence ofany pollution and the best means of prevention.,Since effluents and local conditions vary, the problemis best dealt with by local effort, though centralresearch must be pressed forward and results madegenerally available. The report is evidently impressedby the efficiency and economy of the three group-bodies which are already at work-the Ribble Joint.Committee, the Mersey and Irwell Joint Committee,and the West Riding of Yorkshire Rivers Board.Though these bodies have power to take legal pro-ceedings against offenders, legal process apparently isresorted to only in extreme cases. In most instances,advice and persuasion are found effective, and itseems to be happily the fact that the relations betweenthe Rivers Boards, fishery boards, local authorities, andmanufacturers are cordial and mutually helpful. It isobvious that this is not the time when Parliament canbe asked to pass fresh legislation which may placefurther burdens upon industry. The figures of cost

for efficient treatment of seBvage in particular districtsare sometimes extraordinarily high. Nevertheless, itis reassuring to find that much can be done under theexisting law, that needless, wilful, and remediablepollution can be prevented without interfering withhard-pressed industries, and that there is evidence of akeener popular interest in the purity of our riversthan heretofore. Wider changes in the law and amore closely courdinated study of the problems ofriver purity, land drainage, and water power resourcesmay come some day. Meanwhile the Joint AdvisoryCommittee makes some simple proposals which can betackled forthwith. As appointed by the Ministries ofHealth and of Agriculture and Fisheries, the Committeeis fully representative of local authorities, water andrivers boards, and the manufacturing, fishing, andagricultural interests. Its report carries the greaterweight on this account, especially as it has achievedunanimity. ____

THE PATHOGENY OF ANGINA PECTORIS.

ANGINA has always been somewhat of a stumblingblock to the morbid anatomist, the autopsy findingsare so varied and at times so inadequate. A number ofdistinguished physicians, including Allbutt in thiscountry, Vaquez in France, and Wenckebach inVienna, have found in aortitis an explanation of thesymptoms, but aortitis could only act (if thne wens)a temporary rise in blood pressure during the attack—B"/an assumption which is by no means proved.Mackenzie’s theory that the pain is attributable toexhaustion of the heart muscle is also unsatisfactory.Anatomical evidence in many cases is in favour ofcoronary disease being the determining factor, butthis is not invariably present, and in recent yearsthere has been a tendency to abandon the anatomicalin favour of a physiological explanation which willaccount for the varied post-mortem findings. Theevidence in support of the physiological hypothesisthat angina is due to anoxæmia of the heart muscleis well presented in a recent paper by C. S. Keeferand W. H. Reznik, who, following Heberden’soriginal description, define angina as a conditioncharacterised by pain of a paroxysmal nature provokedby an increase and relieved by a diminution in thedemand made upon the heart. They add that thediagnosis of angina should always imply the likelihoodof sudden death. The similarity of the pain in anginato that in intermittent claudication, as well as theexperimental evidence that voluntary muscles whichare made to contract when their blood-supply isdefective are easily fatigued, and that the contractionis accompanied by pain, strongly supports this hypo-thesis. Further, it is well known that anoxaemia, isan important predisposing cause of ventricularfibrillation. This fact will account for the frequencywith which sudden death is liable to occur in thesecases. In affording an explanation of the persistenceof the pain in coronary thrombosis the physiologicalhypothesis is equally satisfactory; for in that con-dition, unless the anastomoses be sufficient to com-pensate for the occluded artery, the anoxaemia is

permanent and leads to infarction.

THE PARATHYROIDS AND BONE UNION.

MUCH attention has been paid of late to thesignificance of the parathyroids in metabolism, butexperimental work has not yet thrown much light onclinical application. The work of Collip and othershas demonstrated that an extract can be obtainedfrom these glands which can overcome the syndromeof tetania parathyreopriva with its attendant lowblood calcium. The injection of active parathyroidextracts may in animals even lead to fatal resultsaccompanied by very high blood-calcium values.The older observation of Koch 2 that methyl-guanidine appears in the urine of parathyroidectomiseddogs, and of Paton 3 and his co-workers that the

* Arch. Intern. Med., 1928, xli., 770.