27THE FREEZING AND THAWING OF FOOD.

details under each of these headings. Mr. HOLLANDtook care to make his sample of 300 foetuses a mixedone, representative of several districts and of both thein- and out-patient practice of several institutions ;for, as he points out, the incidence of syphili- is higher insome districts than in others, and in-patients, oftenadmitted for severe complications in labour, naturallyyield a higher proportion of dead foetuses than do out-patients.Among the actual causes of death special reference

may be made to syphilis and excessive cranial stress,the first because of its low incidence and the secondbecause of its unexpected importance. The RoyalCommission on Venereal Diseases, unable to obtainmuch information on the relationship of syphilis tofoetal death, had to rely upon indirect evidence, andas a result was led to give great prominence to syphilis Ias a cause of stillbirth. Mr. HOLLAND, on the otherhand, has found a relatively small percentage of deaths Iwhich he could attribute to syphilis. The examinations Iwere thorough and precise ; yet among the 300foetuses there were only 42 cases of proven syphilisand 6 of " probable " syphilis (or 16 per cent. in all) inaddition to 14 cases of " possible " syphilis. Prof.H. TURNBULL’s work on congenital syphilis of the longbones, on which some of the conclusions in the reportare substantially based, appeared in full in our issue oflast week. Mr. HOLLAND’-, observations on excessivecranial stress in the foetus during labour are suggestive.The effects of stress on the shape of the head and on thesepta of the dura mater and of certain cerebral blood-vessels are discussed in detail, and an original theoryon cranial mechanics in the foetus is evolved: Mr.HOLLAND believes that the septa of the dura materact as stays or ligaments to the bones and exert aprotective function during labour, helping to limit thealteration in shape or moulding of the head. Exces-sive moulding leads to tearing of the tentoriumcerebelli and to overstretching and rupture of certaincerebral blood-vessels, the chief of which are the veinof Galen and its tributaries. He describes stress-bands in the septa, disposed on correct mechanical iprinciples in the particular parts of the septa which ’,are liable to be exposed to the greatest strain. Among ’,the 167 fresh foetuses the tentorium cerebelli wasfound torn in 81, associated with subdural cerebralhaemorrhage in all but 6 ; 46 of these foetuses weredelivered by the head and 35 by the breech, thesebreech deliveries representing 75 per cent. of the totalnumber of breech deliveries examined. The frequencywith which the tentorium is torn during a normalbreech delivery has led Mr. HOLLAND to the opinionthat the practice of hastening the delivery of theafter-coming head is responsible for the death of manyhealthy foetuses. Excessive cranial stress is set up bythe forcible passage of the head through a valvalorifice insufficiently dilated and prepared, and a

revision of obstetrical teaching in this respect isurgently needed.Summing up the causes of death in his sample,

Mr. HOLLAND finds 51 per cent. due to complicationsof labour, 16 per cent. to syphilis, 10 per cent. totoxaemia of pregnancy, 2 per cent. to chronic renaland other maternal diseases, 6 per cent. to relativeplacental insufficiency, 5 per cent. to foetal deformity,and lastly some 10 per cent. in which the cause ofdeath was undetermined. A generalisation of someimportance is that more foetuses were killed by thecomplications of labour than died during pregnancyfrom maternal or placental disease. He estimatesthat half of these children might have been saved,20 per cent. by ante-natal care alone, 20 per,cent. by improved technique in treating the com-plications of labour, and 12 per cent. by betterattention at both periods. The two chief means ofprevention of stillbirth suggested in this report are(1) better ante-natal care, and (2) an improvedstandard of midwifery practice, to be attained chieflythrough the better education of the medical student.The report is extremely well produced, containsbeautiful plates, and could with great advantage beread by everyone who attends women in childbirth.

Annotations.

THE FREEZING AND THAWING OF FOOD.

" Ne quid nimis."

A COMPREHENSIVE study by Dr. Walter Stiles, whichhas just appeared as a special reportl to the FoodInvestigation Board, aims at indicating the scientificprinciples on which the preservation of food in thefrozen condition is based. It also considers in somedetail their application to the preservation of twoparticular articles of food-namely, fish and meat.The methods employed in freezing processes are chieflyof technical importance and from the public healthstandpoint the two chief items of interest are a con-sideration of the changes which take place duringstorage and any detrimental effects from thawing.It has to be remembered that the period of storage maybe many months. The changes which may occur areevaporation of water, loss of aromatic substancesdiminishing commercial value, chemical changes dueto autolysis, changes due to the presence of water andoxygen made evident by the development of rancidity,and changes due to the activities of bacteria andmoulds. Evaporation of water depends on the tempera-ture, the relative humidity of the surroundings, themovement of the air over the surface, and the areaexposed. Dehydration is therefore reduced by closepacking, preventing air movement, increasing relativehumidity, lowering the temperature, and using someform of protective covering for the food. Similarmethods diminish the loss of aromatic substances.

Autolytic changes are practically negligible duringstorage. Enzymes survive exposure to low tempera-tures, but are unable to act as catalysts until thetemperature is raised to one suitable to their action.The prevention of rancidity is a matter of the reductionof relative humidity, lowering the temperature, andusing protective wrappers to prevent contact with air.It will be observed that with the lean of meat theproblem is to prevent the loss of water from thesurface, but with the fat it is to prevent the condensa-tion of moisture on the surface. The possibility ofthe development of moulds and bacteria in coldstored foods is of great importance ; here the factorsof temperature and moisture are chiefly operative. Itis well known that most micro-organisms can readilywithstand temperatures a long way below freezing-point. While the vitality of all is lowered at theselow temperatures some of them can still grow, andthe author refers to Brooks and Kidd’s work on blackspot due to a mould cladosporium, which will grow andproduce spores at - 50 C. Dr. Stiles points out that thebacteria in the intestinal wall of fish may fail to comeinto contact with the cold brine and he recommendsthe previous gutting of large fish. The disadvantagesto this course he does not mention. Whether thevitamin content of food is affected by cold storage isstill undetermined, but Dr. Stiles quotes Dr. Hardenas finding that the accessory food factor in butter wasnot diminished by preservation in cold storage.The influence on foodstuffs of thawing is not fully

cleared up. Thawing being the reverse of freezingand therefore governed by the same physical laws, themethod of freezing has a material influence upon theresults of thawing. The more rapid the freezing themore likely are the particles of the substance in thesolid condition to retain the spatial relationships theyhad in the previous. sol or gel condition. In such casesthawing rapidly or slowly conducted is likely to resultin re-formation of the original system. In slow freezingcomparatively big crystals of ice are formed andthawing will then reveal a separation which may bepermanent. Slow thawing will, however, even thengive more time for a possible re-formation of the colloidal

1 The Preservation of Food by Freezing with Special Referenceto Fish and Meat: A Study in General Physiology. By WalterStiles, M.A., Sc.D. Food Investigation Board Special ReportNo. 7. H.M. Stationery Office. 1922. Post free 10s. 3d.

28

system, and is to be recommended from this point ofview. On the other hand, slow thawing possesses theobjection that it gives time for micro-organisrns toattack the surface layers of the meat and so reduce theinterval during which the meat can be kept after thethawing is finished. This aspect of the matter was not,however, experimentally studied and probably a gooddeal of investigation is necessary before the bestconditions for thawing are understood. As regardsfish three methods are practised-i.e., thawing incrushed ice, thawing in water, thawing in warm air-the first and third being slow methods, the second arapid method. Concerning the relative advantages offreezing and chilling as a means of preservation in coldstorage, Dr. Stiles states that the advantage of theformer is so great that it should be one of the objectsof cold storage research to transfer as many foods aspossible from the category of substances to whichmere chilling can be applied to the category of foodswhich can be preserved in the solid frozen state.The report is a valuable addition to scientific litera-

ture and both author and Food Investigation Boardhave put the community in their debt by preparing it.

SYPHILIS OF THE EPIDIDYMIS.

IN an interesting article in the British Journal ofDermatology and Syphilis for June, Dr. A. ReithFraser summarises the recorded cases of syphiliticlesions of the epididymis. Of these, two main types arerecognised, an acute interstitial and a chronic. Theformer is liable to be confused with a gonococcalepididymitis, a point of importance in differentialdiagnosis being that in syphilis the disease usuallystarts within the head of the epididymis, whereas ingonorrhoea the first portion attacked is the globus minor.’The acute form is seen early in the course of the diseaseand gives rise to swelling, pain, and great tenderness.’The chronic form is liable to be confused with chronicgonorrhoeal epididymitis, tuberculous disease, or newgrowths. Examination of the prostatic fluid and theabsence of other signs of gonorrhoea will help to excludethe former. Tuberculous disease and new growthsusually implicate other uro-genital structures and areaccompanied by tell-tale emaciation. The effect ofanti-luetic treatment will usually clear up any doubtthat remains. Dr. Fraser concludes by citing a caseof bilateral syphilitic epididymitis in which the pointsof interest were the following : (1) The diseaseoccurred 18 years after the initial infection ; (2) thelesion on one side was acute and on the other chronic ;(3) the prostate and seminal vesicles were not impli-cated ; (4) both testes were normal. This case ofsyphilitic epididymitis, as usual, rapidly respondedto treatment. The fact that the existence of syphiliticepididymitis is not widely recognised amongstclinicians lends interest to Dr. Fraser’s description ofthe condition.

____

THE THIRD INTERNATIONAL CONGRESS OF

THE HISTORY OF MEDICINE.

As we have already announced, this Congress willmeet at the house of the Royal Society of Medicine,London, from July 17th to 22nd. It will be opened bySir Alfred Mond, the Minister of Health, at 10.30 A.M.on the first day, when the delegates will be received andDr. Charles Singer, the President, will give an address.Academic dress will on this occasion be optional.The sessions will take place morning and afternoon oneach day. The subjects chosen for general discussionare: the History of Anatomy, Veterinary as well asHuman, and the History of Epidemiology from theFourteenth Century. There are also a large number ofpapers promised upon topics of historical interest.Sir Norman Moore will receive the members at theRoyal College of Physicians on Monday afternoon ;the Lord Mayor and Lady Mayoress at the MansionHouse on Tuesday afternoon ; Sir Anthony Bowlbyat the Royal College of Surgeons on Wednesdayafternoon. Visits will also be paid to the Barbers’Hall, to the Apothecaries’ Hall, and to St. Bartho-

lomew’s Hospital. The Congress will conclude with abanquet at the Hotel Cecil on Friday evening.Saturday will be devoted to an excursion to Windsor,and from thence by boat to Cookham, in order thatthe foreign visitors may see something of the beautyof the Thames in summer. The Wellcome HistoricalMedical Museum will be open to members of theCongress throughout the week, and Mr. Henry S.Wellcome issues an invitation to the members to aconversazione on Wednesday evening. Those whodesire to become members should communicate withthe general secretary, Dr. J. D. Rolleston, 21,Alexandra Mansions, King’s-road, Chelsea, London,S.W. 3. The subscription is 21 12s. for members ofthe medical, dental, and veterinary professions, and8s. for their wives, daughters, and sons as associates.Fees should be sent to Mr. W. G. Spencer, 2, Portland-place, London, W. 1. ____

OPERATIONS UPON THE PYLORIC SPHINCTER.WHETHER the wave of deep dissatisfaction with the

results of gastro-jejunostomy as a curative measure,in certain cases of gastric ulce^ is justified or not, thefuture will reveal. It must be admitted, when wereflect in how many thousands of patients the opera-tion has been performed, that the number of realfailures to the discredit of this physiologically verydisturbing procedure, is surprisingly small. Howeverthis may be, the impression of failure has once moredirected the efforts of investigators to the recon-

sideration of operations upon the pylorus as a

substitute for gastro-jejunostomy. The difficulty ofdealing with scarred, or actively ulcerating tissue inpyloric stenosis led most surgeons to give up theHeineke-Mickulicz method of pyloroplasty, and forthis very reason and the added difficulty of mobilisingthe duodenum, especially in the presence of adhesions,Finney’s operation has never become very popular.A method which restores the natural mechanics ofgastric evacuation has many attractions, and islikely to be followed by satisfactory results as theafter-histories of the 43 patients reported on byG. Grey Turner 1 show. J. S. Horseley, 2 who hasmodified the original Heineke-Mickulicz operation,and combined it with excision of the ulcer, has alsoobtained distinct encouragement for his procedure.The real stimulus to the revival of interest in

pyloroplasty has been the exceedingly gratifyingresults which have been obtained in congenitalhypertrophic stenosis of the pylorus by employingRammstedt’s method. The investigations of G. H.Miller, H. H. Bowing, and L. L. Stepp into the relativemerits of certain operations upon the pyloric sphincter3are bound to influence the choice of such operations.Their experiments were performed upon normaldogs. They found that a typical Heineke-Mickuliczoperation is followed only by a temporary increase inthe size of the pyloric ring, and a similar ultimatereclosure ensued, when, by an ingenious technique,a portion of stomach wall was sutured between theends of the divided sphincter. After Rammstedt’soperation they were able to show that the arrivalof a peristaltic wave at the pylorus tended rather toincrease the size of the ring and the bulging of themucous membrane. After death the cut edges of themuscular coats were still gaping widely. C. A.Pannett4 showed in an experimental investigationthat this result cannot always be depended upon.The incision may heal as a linear scar. W. A. Downes5has observed this to occur in children without evileffect, because, it has been suggested, the hyper-,trophied sphincter does not increase in size andstrength at an equal rate with the rest of the stomachmusculature, so that the disproportion between therelative strengths of the pyloric sphincter and thepropulsive power of the stomach disappears with age.

1 Surg., Gyn., and Obstet., 1912, xiv., 537.2 Journ. A.M.A., 1919, lxxiii., 575 ; Ann. Surg., 1921, lxxiii..

199 ; with W. T. Vaughan, Journ. A.M.A., 1922, lxxviii., 1371.3 Surg., Gyn., and Obstet., 1922, xxxiv., 763.

4 Brit. Jour. Surg., 1921, viii., 31.5 Journ. A.M.A., 1920, lxxv., 228.