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Taking all these observations together there seemsto be an excellent case for regarding a rapid transitof blood through the placenta as the cause of theobstructive circulatory changes in the lower extremitiesduring pregnancy. The return of blood to the heartis said to be facilitated by the opening up of thealternative subcutaneous abdominal route. Thiscan be beautifully demonstrated by infra-red photo-graphy, and there is no doubt that the abdominalvenous network becomes more and more distinctas pregnancy advances. Gorman and Hirsheimer, õ

however, after a thorough exploration of the infra-red photographic method, express some doubt as

to whether the increased visibility of the sub-cutaneous vessels necessarily means they are carryingmore blood. They point out that while the changesare undoubtedly progressive in any one patient,in a group of women the veins of some who are notpregnant may photograph better than those of somewho are. The measurement of venous pressuresseems to have provided the most significant evidence

DRUGS IN CORONARY DISEASE

THE commonest cause of coronary obstruction isatheroma; no remedy is yet available which directlyaffects this condition. Drugs are therefore only usefulin the control of symptoms and complications, andas most of those ordinarily used have unfavourableside-effects they should not be given unless reallynecessary and then with caution. Gold 6 points outthat though the value of some of the drugs recom-mended is proved that of others is doubtful. Thenitrites are still the most valuable in the relief orprevention of effort angina, though their action istransient. Glyceryl trinitrate tablets absorbed fromthe mouth may be effective in small doses (gr. 1/200-1/150) if taken at the onset of the pain. When painarises on slight provocation tablets may be requiredvery often, and it is stated that fifty or more maysafely be taken daily. In such a case, however, it isnecessary to exclude a recent myocardial infarct orrecurrent multiple small infarcts, for it is then betterto avoid pain by absolute rest than by vasodilators.The subject with effort angina is a potential victimof myocardial infarction in which vasodilators maybe harmful, and he should be warned against usingsuch drugs repeatedly for any anginal pain of morethan a few minutes’ duration, especially if it comeson at rest. It has been claimed that the xanthinederivatives, such as Diuretin and Euphyllin, are

valuable both in effort angina and myocardial infarc-tion, and they are extensively used for these condi-tions, but there have been no controlled clinical orexperimental observations to justify these claims.This group of drugs may be rationally used, however,as diuretics, and one of them (euphyllin) may abolishCheyne-Stokes breathing. When cardiac infarctionis accompanied by severe pain morphia is required,but the large doses sometimes needed lead to meteor-ism, depression of the respiratory centre and possiblyectopic rhythms, though the heart condition itselfcan produce any of these symptoms. Gold suggeststhat not more than gr. 4 of morphia should be givenat a time, that this should not be repeated oftenerthan once every half-hour and that a total of more thangr. 1 in twelve hours is rarely wise. He regards codeinegr. i-1 with or without scopolamine gr. 1/150 as agood substitute for morphia, especially where a mildpain persists for several days. In most cases a continu-ous mild sedation is helpful and for this the barbi-

5. Gorman, W. A., and Hirsheimer, A., Surg. Gynec. Obstet.January, 1939, p. 54.

6. Gold, H., J. Amer. med. Ass. Jan. 7, 1939, p. 1.

turates-e.g., phenobarbital-are suitable. For cardiacinfarction without complications digitalis is not onlyunnecessary but probably harmful, but with heart-failure, or auricular fibrillation, or flutter with fastventricular rates it must be given, though in rathersmaller than ordinary doses since in the acutelydamaged myocardium ectopic rhythms are more

readily produced. Quinidine may be called for inventricular tachycardia but not otherwise. Measuresto increase venous return are indicated for shock, andadrenaline for Stokes-Adams attacks. Gold rightlydeplores the use of muscle extracts in the treatmentof coronary disease, since there is no properly controlledevidence of their value.

DENTAL CARIES

ACCORDING to R. W. Bunting and his co-workersin the Michigan school the most significant causativefactor in dental caries is the presence and degree ofactivity of Bacillus acidophilus in the mouth, but theincidence of caries may be increased by the additionof relatively large quantities of sugar to the diet.These findings are hardly supported by the resultsof a small-scale investigation reported by King andCrolP Using eight institutional children in Sheffieldand thirty from the relatively caries-free countrydistricts of the Isle of Lewis they first related theincidence and extent of caries to the B. acidophiluscontent of the saliva. In the town children no

association could be detected ; in the others a

comparatively low count or complete absence ofB. acidophilus was found in the majority of thecaries-free mouths and a high count in half those withactive caries. On the other hand two of the caries-free had a fairly large number in the saliva while halfthe carious had relatively low counts-two, in fact,were completely negative. There is certainly somesuggestion of an association between the variablesin these figures, but it is obvious that strikingexceptions are not infrequent. With the eightSheffield children the authors next endeavoured totest the effects of the daily addition to the diet of2 oz. of sweets in the form of toffee for ten weeks,after which the children rebelled and accepted choco.late caramels for a further six weeks. With such asmall number of observations the results must berather indeterminate. Two children showed no

change in their number of carious cavities and littlechange in the number of colonies of B. acidophilzcs.In the other six there was some increase in cariousactivity, but how much might have been expectedwith mere lapse of time is unknown ; three showedalso an increase in B. acidophilus ; two no materialchange ; while one remained negative throughout.The authors are rightly reluctant to draw definiteconclusions from so small an experience, but they areunable to find in it a corroboration of Bunting’s views.On the other hand Schi6tZ 2 of Oslo presents more

evidence in support of the relation between dentalcaries and nutrition. Of pupils in the Oslo elementaryschools only 2 in every 1000 have, he says, faultlessteeth. This is a small number, and for the purposes ofthe inquiry those defined as having excellent or goodteeth were added to them and 200 children thusobtained. Dietary histories were obtained from theirmothers and Schiotz thought that these showeda more regular use of protective foods and a smallerconsumption of sweetstuffs than in the populationin general, but no control group is available. More

convincing is the evidence that the children with goodteeth are largely segregated in a few schools, the

1. King, J. D., and Croll, J.M., Brit. dent. J. Jan. 2,1939, p.19.2. Schiötz, E. H., Ibid, Jan. 16, 1939, p. 57.

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average number being 17.6 per 1000 in five schoolsagainst 0.3 per 1000 in four other schools, and 2.7per 1000 in the remainder. Various measures ofsocial status show that the good teeth come mainlyfrom the economically better-situated families. Inaddition Schiotz gives some figures from isolated ruraldistricts where the " old-time natural manner of

feeding " is maintained. Of 127 children examined,with an average age of nearly eleven years, 17 percent. were free from caries, and of 2136 permanentteeth (present and extracted) 27 per cent. were

attacked (carious and filled and extracted) ; muchbetter figures than those presented for Oslo. Investiga-tions were also carried out at 23 infant homes com-

prising 338 children and the resulting figures showthat the earlier in life the children come to the homethe better are their teeth. With regard to sugarconsumption an interesting comparison is madebetween two homes. The children in Alfredheimhave far worse teeth than those at Trysil. The

consumption of milk, coarse bread, butter and fruitis about the same at each home ; the Alfredheimchildren eat more vegetables and potatoes; while theTrysi) children have about two and a half times asmuch sugar. At Trysil, however, all the children havecod-liver oil daily in the winter, whereas at Alfredheimthey have it only when ordered by the doctor.

INJURY AND DISEASE

IN an interesting article which appeared in the

Magazine of the University of Leeds medical society,Dr. G. F. Walker discusses some of the problems ofthe relationship between injury and disease. Hedivides the illnesses which may follow injury intoeight classes and gives examples of each, drawingupon his personal experience to illustrate his points.He emphasises quite rightly the importance of thismatter in forensic medicine. So much attention isnow being paid to the subject in the courts that,at least as far as injuries arising out of and in thecourse of employment are concerned, the workmen’slegal advisers assume with apparent authoritythat any disease appearing subsequent to an injuryis part and parcel of that injury, or in legal phraseology"caused, precipitated or aggravated by it." Thus,contrary to the first principle of British justice, anonus of disproof is thrust upon the medical advisersfor the employer.Much research work needs to be done so that

definite guidance may be given to the courts aboutthis. A start could be made by defining injuryand disease. Accident-insurance companies haveendeavoured to describe the peril insured against asa morbid condition due to injury " caused by violent,accidental, external and visible means." Although atfirst this may have seemed clear enough, succeedingjudgments given in the courts have succeeded in sowhittling down the previously accepted meanings ofthese words that almost the whole range of diseasecan be covered by them. For instance, " violent "

means the contrary of " without any violence at all."As an example, an elephant trampling on a fly maybe an original example of violence; but now thefly trampling on the elephant would be held to be"not without any violence at all." Similarly," visible " may now be interpreted as " discernibleby a medical man." In contradistinction to " injury,"disease may be held to be a morbid condition whicharises and runs its course without any history or

clinical evidence of injury. This definition, however,is obviously not sufficient in itself and it may bedesirable for some scientific body of medicine to

supply the deficiency.

After satisfactory definitions have been given itwill then be necessary to search for proof of relation-ship between the two. No doubt there is often someconnexion between injury and disease and it is easyto quote cases in which disease appears to have arisenfrom definite injury. One of the best examples iscarcinoma of the tongue arising from repeated traumaby an ill-fitting dental plate. Another example is the" surgical kidney " following prolonged instrumenta-tion for the treatment of a traumatic stricture of theurethra. It is quite otherwise with generalisedepilepsy or tumours of the brain ; although in thelaw-courts these conditions are constantly beingattributed to injury, scientific proof is wanting inmost if not all the cases. Little has been done in the

investigation of normal controls although in somedirections a beginning has been made. Among 431cases of glioma Parker and Kernohan 1 found in13-4 per cent. a history of injury at some previoustime in the lives of the patients. In a control groupof 431 consecutive victims of various other diseasesthere was a history of injury in 10.4 per cent. Among200 presumably normal persons there was a historyof injury in 35-5 per cent. ; the relative severity ofthe injury was highest in the normal group. Among10,452 cases of gunshot wound of the head occurringin the United States armed forces during the latewar, Pollock 2 did not find any case of brain tumour ;and of the 40 cases of cerebral tumour occurringamongst U.S. veterans and operated on by LoyalDavis 3 not one had been wounded and only twogave a history of head injury.

In fulfilling the " onus of disproof " the medicalwitness may have little difficulty in showing that thecause of a particular disease was not a particularinjury, but it is often difficult to give a direct negativeto a statement that disease was precipitated in a

person who was already destined to suffer it, or thatdisease had already started or had been latent andbecome aggravated by the injury. Only an accurateknowledge of the usual course of the disease, itsaccelerations and exacerbations, and a detailed

history of the condition of the patient from the onsetof the disease or the accident, with a full account ofany bridging symptoms, will enable the examinerto form a valid opinion.

BARBITURATES AND LIVER DAMAGE

SOME of the barbiturates are detoxicated by theliver whereas others are excreted straight away by thekidney. The latter are generally those of quickaction, such as Evipan and Pentothal, while theformer are typically represented by Nembutal.An2esthetists ordinarily withhold barbiturate pre-medication from patients with any form of liverderangement and the work of Cameron and de Saram 4at University College Hospital medical school showsthat the need for caution may be present even beforethe liver can be known to be imperfect. Experi-mentally rats with acute liver damage provedabnormally susceptible to both nembutal and evipan ;this effect quickly passed off when liver regenerationset in. With progressive liver damage the action ofnembutal was much enhanced long before seriousstructural damage appeared in the organ, and it is

suggested that impairment in detoxifying functionprecedes the development of obvious structuralchange. Some observers it is true have obtained

1. Parker, H. L., Kernohan, J.W., J. Amer. med. Ass. 1931, 97, 535.2. Pollock, L. J., quoted by Brahdy, L., and Kahn, S., Trauma and

Disease, 1937, p. 317.3. Davis, L., quoted by Brahdy and Kahn, Ibid.4. Cameron, G. R., and de Saram, G. S. W., J. Path. Bact.

January, 1939, p. 49.