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of Hodgkin’s disease ; (2) there was no clinicalresemblance to streptococcal septicaemia until, liter-

ally, the last few hours ; and (3) if the streptococcalinvasion is to be regarded as a "terminal" event,when exactly did the new infection come into thepicture’ f The granulomatous deposits in the liver,and the curious improvement in the state of the glandsin one situation followed by enlargement of glands inanother place without any obvious fresh primaryfocus, are facts which have to be faced if the

lymphadenomatous nature of the case is denied ;the question of such disorders as glandular fever orleukaemia can be excluded by the blood picture.We would, therefore, submit that in the present

case the tissue response to streptococcal infection was iof the nature of an infective granuloma resembling

Hodgkin’s disease, and we would repeat our plea forthe frank abandonment of too rigid a classification ofthe disorders of the blood, lymphoid elements, andreticulo-endothelial system as they occur in childhood.In this way only, we believe, are there possibilitiesfor the advancement of knowledge.

SOME PRINCIPLES REGULATING THE LIFE

AND DEATH OF

PATHOGENIC INTESTINAL BACTERIA

IN ARTIFICIAL MEDIA AND IN FRUIT JUICES.

BY MACKENZIE DOUGLAS, M.D. EDIN.

(From the Ross Institute and Hospital for TropicalDiseases, London.)

RECENTLY interest has been shown in the possi-bility of combating bacterial infections by means ofdiet. If it were possible to treat the intestinal tractas if it were inert, then the problem would be easy,because bacteria can be destroyed in the laboratorywithout the aid of harmful antiseptics. As this doesnot seem to be generally appreciated, it may be ofuse to discuss some of the principles which governthe growth of bacteria outside the body.Many organisms which produce acid in culture

media containing carbohydrates will give rise toalkali if cultivated upon media containing onlyproteins. This faculty of breaking up carbohydrateswith the production of acid or of acid and gas is

largely used for differentiating organisms into types.Let us first, however, consider what happens in asimple media consisting of water with 0-5 per cent.common salt and 1 per cent. peptone. Sierakowski 1

has shown that during the first four days the bacteriaregulate the medium so that most of them reachneutrality; alkaline media are acidified and acidmedia are alkalinised.

Bacteria grow most rapidly in a culture mediumwhich has originally the hydrogen-ion concentrationwhich they try to reach in the first four days-e.g.,B. coli and V. cholerce at about pH 7’6, and B. dysen-teriae (Shiga-Kruse) at 6-8. The further the hydrogen-ion concentration is originally from this point theslower is the initial growth. Without growth nochanges in pH are observed, this change being there-fore strictly a function of growth processes. Afterfour days all bacteria tend to change the media tothe alkaline side. Bacteria grown on sugar-freemedia produce alkaline substances the chemicalnature of which is unknown, and at the same timecarbon dioxide is liberated and increases the acidity I

of the media. The more opportunity there is for theescape of carbon dioxide, the more rapidly do thecultures become alkaline-e.g., in loosely pluggedculture tubes with a surface that is large in propor-tion to the depth. Hermetically sealed tubes do notbecome alkaline, but if to these sealed tubes sodalime be added to absorb the carbon dioxide, thenalkalinisation goes on as rapidly as in open tubes.Later the production of alkaline metabolic productsleads to gradual alkalinisation.

Formation of Acid and Death of Organism.If a sugar or carbohydrate, however, is present in

the media, one of two things happens: first, thebacteria may not break up the sugar, which remainsunchanged, and the result is the same as if the mediawere sugar-free ; or, secondly, the bacteria maybreak up the sugar with (a) the production of acidor (b) the production of acid and gas. The actionremains constant for any number of generations. Ihave shown in experiments previously published 2that the acid production in glucose peptone water isindependent of the number of organisms placed inthe medium to start with. That is to say, if in onetube containing 1 per cent. glucose peptone waterone B. coli be introduced, and into anotherexactly similar tube 250,000 B. coli, then at the endof 42 hours’ incubation there will be the same numberof organisms, roughly speaking, and in both tubesthe pH will be the same. With B. coli the pH willalways be 4-2, which is the maximum acidity attainedand is quite constant for this organism. It is truefor all strengths of glucose peptone water if therebe at least 0’35 per cent. of glucose present. If therebe 0’3 per cent. of glucose or less, then the pH willbe less acid than 4-2, and if only 0-15 per cent. ofglucose be present then the media will becomeneutral, and in eight days will even go to the alkalineside. The acid production varies in degree with thedifferent bacteria-e.g., the p-H with B. typhosus inglucose peptone water is 4-4 and is constantly atthat figure. If daily subcultures are made fromthese tubes of glucose peptone water, inoculatedwith either B. coli or B. typhosus, it will be foundthat, when the percentage of glucose is 0-35 per cent.or higher, the tubes are sterile on the fourth or fifthday, while in the tubes with 0’3 per cent. of glucoseor less the organisms live for at least three weeks.In fact, in glucose-free peptone water or brothB. coli have been found alive after a year.

If instead of peptone water bouillon made frommeat be used, the pH reaches only a figure of 4’4with B. coli, and that only if 0-4 per cent. of glucosebe present ; the organisms die on the eighth day,taking much longer than when peptone water isused. If only 0-25 per cent. of glucose is present,the medium is on the alkaline side of neutrality onthe nineteenth day and the organism continues

living. Although it is common in culture media touse 1 per cent. of glucose, actually only a portion ofthis is broken up. Sufficient acid or substances of anacid reaction are produced to prevent further growthand cause death within a few days. This lethalaction is closely related to the acidity or hydrogen-ion concentration. The actual acid formed differswith the sugar present in the media, as well as withthe organism tested. B. coli grown in glucose pro-duces carbonic acid and an inflammable gas, whichis a mixture of hydrogen and marsh gas. B. typhosusin a similar medium produces lactic acid, but nocarbonic acid or other gas. In other cases acetic,oxalic, formic, and hippuric acids are formed.

790

The formation of acid, then, is the explanation ofthe death of the bacteria. A possible reason for theretarding of the lethal effect, when broth in used,may be found in the work of Koessler and Hanke.3 3

Working with B. coli, they found that the veryhighly toxic base histamine is obtained from theamino-acid histidine by the splitting of carbon dioxidefrom the acid group of the amino-acid. This hista.mine production by B. coli was found only in cultureswhere considerable quantities of acid were producedat the same time. This strongly basic substanceoffsets, to some degree, the acid production, andenables the organisms to develop further before thehydrogen-ion concentration reaches the point ofinhibition.

Peptone waters with varying known hydrogen-ionconcentrations can be prepared by adding varyingquantities of N/10 sodium lactate and N/10 lacticacid to 1 per cent. peptone water which does notcontain any glucose, producing a " buner " action.It was found in these stable media that B. coli diedon the second day in the media with a pH of 4-2,but was alive in the tubes with pH of 4-3 and 4’6.In another experiment with B. paratyphosus A, theorganisms died on the second day in the tube withthe pH 4-3, but was growing in the tubes with pH 4’6and 4-7. These tubes connected the lethal effectmore definitely with the acid production.These are laboratory experiments, and it will be

readily understood that the conditions inside thehuman body are quite different. Otherwise it wouldbe easy to control the flora of the intestine and cureintestinal inflammations. In the first place glucose,if given by the mouth, is quickly absorbed. It isalso absorbed if given through an appendicostomyopening. In one case, in which this was done in apatient with a very prolonged colitis followingbacterial dysentery, no glucose was found in thefaeces and their pH was only slightly acid. Again,coli organisms are not found in the stomach, wherethe reaction is acid during digestion and continuesacid. It is, of course, possible for these organisms topass through the stomach with sufficient rapidity toescape death, but they do not find the stomach andupper part of the intestinal tract a suitable nidus fortheir growth. It is interesting to note, however,that in some cases of cancer or of pernicious ansemiawhere there is a lack of acid in the stomach, B. <wKcan be found in the small intestine at a much higherlevel than in healthy people. These remarks referto the Gram-negative intestinal bacilli as well as tostaphylococci and streptococci. They do not refer,in the same degree, to yeasts and to the acidophilbacilli, to which group belong the Bulgar bacillusand bacillus of Boas, which can occasionally be foundin the stomach contents. After acid fluids passthrough the stomach they are soon diluted and comein contact with alkaline bile and other alkaline bodyfluids, so it is difficult to imagine that the contentsof the small or large intestine could have for 24 or48 hours a pH in the neighbourhood of 4-2. Theseare the conditions that would be necessary to con-form to those we have in the experiments describedabove.

Action of Fruit Juices.

The acidity of fruit juice varies within certainlimits according to the different specimens, but thefigures given are representative of fruit bought inMarch and April of this year. The juice of orangeshad a pH of 3-2 and 3-4, the juice of a lemon waspH 2-0, the pH of tinned peach juice was 3F, and thejuice expressed from an apple was 3-5. Orange juice I

killed B. typhosus in times varying from 9 to 22

hours, B. paratyphosus A from 9 to 30 hours, B. coliand B. paratyphosus B in 48 to 120 hours. Tinnedpeach juice killed B. typhosus and B. paratyphosus Ain 30 hours, B. coli and B. paratyphosus B in 72 to120 hours. The juice of a lemon killed B. coli in 6hours, although there was very great diminution inthe number after 3 hours. B. paratyphosus A,B. paratyphosus B, and B. typhosus were alldead in 3 hours. Undiluted lemon juice killedB. typhosus in from 5 to 9! minutes. The bacilliwere killed in 15 minutes by dilutions of 1 in 2 and1 in 4, while a dilution of 1 in 16 took 6 hours.Lemonade made from the juice of one lemon, twoteaspoonfuls of sugar, and ten ounces of water had apH of 2-8. In ten hours it killed B. typhosus, B. para-typhosus A, B. paratyphosus B, B. dysenteriae Flexner,and B. dysenteriae Shiga, and very nearly killedB. coli in that time. Staphylococci were killed in 5hours.

In every case about two teaspoonfuls of thedifferent fluids were employed in the experiments withabout 2,000,000,000 of the different organisms. Thiswas a fairly exacting test, as it would be difficult innatural circumstances to get such a concentration ofbacteria.

Apple Pulp and Treatment of Dysentery.Finally, several experiments were done with apples

made into a pulp and boiled both with and withoutsugar. The pH varies in this case according to thedilution with water. The results recorded were witha pulp such as would be pleasant for eating and hada pH of 3-6. Two teaspoonfuls of this pulp were putin test tubes and mixed with 2,000,000,000 of variousorganisms and kept in the incubator. Subcultureswere made at periods. There was very little differ-ence in the results, whether the apple was boiledwith or without sugar. B. dysenterice Shiga was deadin 10 hours ; B. dysenterica Flexner and B. typhosuswere dead in 48 hours, but the subcultures showedonly slight growth after 10 hours. B. paratyphosu8 Ashowed very slight growth in 10 hours and was deadin from 24 to 30 hours. B. coli and B. paratyphosus Bwere still alive at the end of 48 hours. Six strains oiB. paratyphosus B were tested and all showed thisresistance to the action of apple pulp, in contrast toB. paratyphosus A, which was very sensitive. As acontrol, experiments were done at the times indicatedas those at which the organisms died. Peptone waterwas added to the tubes to dilute the media and thetubes were then incubated. This proved definitelythat they were sterile and that the subcultures in theprevious experiments were not due merely to specialportions of the media being sterile.

This last experiment is of special interest on

account of the statement by Prof. Moro of Heidel-berg. He states that he can cure children sufferingfrom dysentery and from acute and chronic diarrhcea.For two days he gave 20 to 50 oz. daily of ripe applesmade into a puree, equivalent to 7 to 20 moderate-sized apples. Nothing else, not even water, wasgiven for two days. I have had no experience of thisform of treatment, but it is to be noted that, fromthe in vitro experiments, the method of giving theapples, so that dilution is reduced to a minimum,seems that which would be most likely to give satis-factory results. It seems feasible that where an acidfluid might fail because of the ease with which itwas neutralised, apple in bulk might not be so actedon, and might release acid in that part of the intes-tinal tract where the inflammation is situated. DL

791

J. W. Dickson states that this method was employedby Jenner in cases of enteric, and quotes some ofhis own experiences. This form of treatment is sureto have a trial and the results will be awaited withinterest, but it is most important that the methoddescribed should be adhered to so that the pH isdisturbed as little as possible by dilution. If thistreatment should prove of value, then I think it willbe found that the explanation is on the lines of theexperiments given in this paper.

Summary.Gram-negative intestinal bacilli produce in glucose

and some other sugars acids, which cause their deathin peptone media in a few days. Each variety pro-duces acid till a maximum hydrogen-ion concentra-tion is attained. This concentration is constant foreach variety of bacillus. It is 4-2 for B. coli and 4-4for B. typhosus. Fluids with acidity below 4.2 causedeath of the organisms rapidly, the rapidity depend-ing largely on the degree of acidity. Two teaspoonfulsof the juice of a lemon kills 2,000,000,000 B. typhosusin less than ten minutes. In the body this acidityis rapidly neutralised after it leaves the stomach,but it seems reasonable that apple pulp might beeffective where a fluid would be neutralised.

LITERATURE.

1. Sierakowski, S. : Biochem. Zeit., 1924, cli., 15.2. Douglas, M.: Jour. Trop. Med. and Hyg., 1929, No. 6, xxxii.,

75.3. Koessler, C., and Hanke, M. K.: Jour. Biol. Chem., 1919,

xxxix., 539.4. Moro, E. : Klin. Woch., 1929, viii., 2414 : see THE LANCET,

1930, i., 526.5. Dickson, J. W. : THE LANCET, 1930, i., 672.

SPONTANEOUS PNEUMOTHORAX.

BY H. E. SYMES-THOMPSON, M.D. CAMB.,M.R.C.P. LOND.,

PHYSICIAN TO THE ROYAL CHEST HOSPITAL, CITY-ROAD, LONDON.

(WITH ILLUSTRATIONS ON PLATE.)

By spontaneous pneumothorax is meant a conditionin which air has escaped into the pleura by nature’smeans; the term is used in contradistinction toartificial pneumothorax, in which the air has beenintroduced into the pleura by the physician. Bothconditions, therefore, have this in common, that airis present in the pleura. They differ in that the aircame from the lung in spontaneous pneumothorax,its admission being due to rupture of the lung intothe pleural cavity ; whereas in artificial pneumothoraxthe air came from outside the body, and gainedentrance not by natural processes but by means ofa trocar and cannula. The induction of artificialpneumothorax is now a commonplace in the diagnosisand treatment of diseases of the chest. By thismeans, under favourable circumstances, the lung canbe collapsed to any extent up to complete compressionagainst the spine, the degree of compression beingunder control. Similarly, in spontaneous pneumo-thorax the amount of compression of the lung varies.There may be but a small escape of air into the pleura,compressing only a small portion of the lung, furtherspread being limited by pleural adhesions. In othercases various intermediate degrees of compressionmay be found. Finally, in the most marked instancesthe escape of air may be so great as to compress thewhole lung completely.

etiology.pojitaueoub pneumothorax, which was first des-

cribed by Itard in 180:3, occurs more often on theleft than on the right side ; it is found complicatingvarious conditions, notably pulmonary tuberculosis.Biach 2 analysed 918 hospital cases, and of these715, or 77’7 per cent., were in this category. Of the

remaining 203 cases, 65 complicated gangrene of thelung, 45 empycma, and 32 wounds of the chest.

Among other cases may be mentioned those whichfollow the rupture of an emphysematous bulla, inpeople who may have been previously in good health(Case 1) ; and also those which develop during aparoxysm of asthma (Case 2). The literature showsthat pneumothorax thus complicating asthma is avery rare occurrence. Recent advances in knowledgehave made it possible to demonstrate spontaneouspneumothorax in various conditions in which its

presence was previously unsuspected, particularlywhen the pulmonary collapse is incomplete. It

may, therefore, be the case that Biach’s figuresexaggerate the actual preponderance of pulmonarytuberculosis as a precursor of spontaneous pneumo-thorax.The cause of spontaneous pneumothorax in pul-

monary tuberculosis is the breaking down of a lesionsituated close to the pleura and perforating its viscerallayer (Case 3). The reason why the complicationdoes not occur more often in pulmonary tuberculosis-the site of which is so often near the periphery ofthe lung-is that the overlying pleura is usuallythickened and often adherent.

Symptoms and Diagnosis.In a typical case of complete spontaneous pneumo-

thorax, in which so much air has entered the pleurathat one of the lungs has become completely collapsed,the history tells of an illness with an acute onset,ushered in by sudden and continuous thoracic painor discomfort which is usually confined to the

neighbourhood of the lung rupture. The patient sitspropped up in bed, breathing rapidly, and sweatingin the face. The pulse-rate is between 120 and 140per minute. He is, in fact, gravely ill and, whencomplete spontaneous pneumothorax occurs inadvanced pulmonary tuberculosis, this complicationoften ends his life. The heart is found to be drawntowards the uncollapsed lung. The chest does notmove over the collapsed lung during respiration.Vocal fremitus and vocal resonance are cut off, andthere may be hyper-resonance on percussion. Butthe most strikingly characteristic sign of the conditionis discovered on auscultation ; on the collapsed sidethe breath sounds cannot be heard. This is a silenceof emptiness, but, just as in an empty building smallmovements strike the ear, so in an empty chestcertain sounds, small at their points of origin, mayreverberate in the cavity and become modified incharacter. For instance : (1) over perhaps a smallarea only, we may hear blowing or cavernous breathsounds ; (2) we may hear’ musical rales-metallictinkling ; (3) if two coins are hit together on thechest wall, we may find, on auscultation, that thesound produced becomes bell-like in quality. Thiscoin sound, however, is often absent. If cavernousbreath sounds can be heard we may assume that the holeinto the lung is still patent, and if, a day or two later,they can no longer be heard, it -would be evidencethat the hole had closed in the interval. The spleenor the liver respectively may be found displaceddownwards, according to which side is involved. In

p2