452 VASCULAR SPASM AND ASTHMA

sentimental philanthropy but biologically well-founded economics. These are a few of the medico-biological considerations to be taken into accountby legislators. There remains the recent sinisterincrease in juvenile accidents, which suggeststhat some cumulative strain is already in action,and the admitted strain which even normal hoursof work may throw upon the young persons in

occupations where there are loads to be lifted.And we are unaware of any systematic researchto assess the effects of two- or three-shift systemsupon the development of young people.The positive evidence of the good effects of

properly regulated employment for the age-group16-18 should not be forgotten ; and it is un-

doubtedly possible to combine wage-earning witheducation in a way that fulfils the chief needs of

many boys and girls. The reports of the con-tinuation schools at Rugby and York and Birming-ham could be re-read with advantage. But itseems to us that anyone who employs young peoplemust be able to show that the conditions are

reasonable: and we should regard night-work asguilty until proved innocent rather than innocenttill proved guilty. Whatever may be the economic

pressure on juveniles for night-work, for overtime,or for two-shift systems, it must be resistedin view of the medical evidence--even if this doesnot amount to proof-that such kinds of workbetween the ages 16-18 are biologically unsound.They must be unsound, because they are likely tointerfere with the normal processes of growth.Happily it is not for the medical profession todecide between the rival claims of economics andhealth ; its task is to state the truth so far as itis able to do so, and on the evidence available to it.On this evidence, as it at present stands, overtimeand night-work are not to be tolerated for adoles-cents, and we hope that Parliament may be

persuaded to amend the present Bill so that, forthose under 18 years old, the 48-hour week is

exchanged for a maximum of 40 hours employmentwith 7-8 hours’ education and recreation.

VASCULAR SPASM AND ASTHMA

THE distribution and function of the bronchialarteries has long been a matter of interest toProf. I. DE BURGH DALY and his colleagues. Theywere led to its study in their search for the methodof vascular adjustment in the lungs, the con-

tractility or otherwise of the pulmonary arteriolesand capillaries being in dispute. For practicalreasons, indisputable information about thebehaviour of the pulmonary vessels can beobtained only from a preparation of isolated lungs,and Prof. DALY felt that preparations of this sortin the past had perhaps lacked something vital inthe shape of a blood-supply through the bronchialarteries. An analogy would be a preparation ofthe surviving heart in which a perfusion of thecoronary circulation was omitted. Perfusion ofthe bronchial arteries as well as the pulmonarydid, in fact, reopen the whole question of vascularcontrol in the lungs. The pulmonary circulationwas now found responsive to nerve stimulation,

whereas before it had been inert. Vasoconstrictionand vasodilatation were readily demonstrable.This was attributed to survival in the lungs ofnerves which in previous experiments had quicklyperished from ischaemia of the tissues in which theywere embedded. Since histological and anatomicalstudies show that the bronchial vascular

system supplies every tissue of the lungs exceptthat part of the respiratory tract distal to the

respiratory bronchioles, it may be assumed thatthis explanation is the true one. The correlationof an active pulmonary vascular bed with the restof the circulation raises many problems and offerswide opportunities for speculation.l

Quite a different point, of immediate practicalimportance, has also been raised by Prof. DALY. 2The bronchial arteries supply not only nervesbut the bronchial muscles themselves. Interferencewith the circulation might therefore affect thesedirectly or indirectly, and a new setiological possi-bility is opened up with regard to asthma. Isasthma sometimes due to vascular spasm or disease ?The answer to this question is not to be found inthe laboratory. The most the physiologist can dois to demonstrate the effect on bronchial move-ment of interfering with the .bronchial arteries,and so bring a prima-facie case. The final investi-

gation must be made at the bedside and in thepost-mortem room, and few will dispute the

urgency of beginning this at once. Prof. DALYhas pointed to the first path to be followed.

" To

us," he states, " it is becoming increasingly clear

that ... there should be a wider histologicalexamination of the bronchial arteries in all pul-monary cases which come to post-mortem examina-tion, for it is only by this means that we shall beable to obtain information as to whether the

suggestive physiological experiments I have des-cribed are of significance in relation to the controlof intrinsic mechanisms of the lungs during life."Those who doubt the significance of these experi-ments will realise the importance of justifyingtheir scepticism by tangible evidence, and wecommend the suggestion of examining bronchialarteries post mortem in pulmonary cases to theattention of morbid anatomists. Fortunatelyuncomplicated asthma rarely leads to death, buta good deal of relevant information must surelybe obtainable from fatal cases where asthma has.been part of the history.

INTESTINAL ADSORBENTS

IN the Far East kaolin or china-clay has probablybeen used for many centuries in the treatment ofintestinal complaints. PÈRE DEUTRECOLLE, theJesuit missionary to whom we owe much of ourknowledge of the Chinese potter’s technique inits later but still golden period, writing in 1712mentions its employment for the relief of diarrhoea.Of late years it has been established in Westerntherapeutics, mainly on a basis that must beadmitted to be highly speculative. That fuller’s

1 Harvey Lectures 1935-36, Baltimore, p. 235.2 Trans. med.-chir. Soc. Edinb., 1936, p. 139. (Edinb. med. J.)

453INTESTINAL ADSORBENTS

earth, kaolin, and other silicious earths are-to usethe modern term-adsorbents may be looked uponas a very ancient discovery, since their propertiesas cleansing agents, and decolorisers, and even

their capacity for taking glazes when baked,depend upon their adsorptive powers. But it is

only with the growth of modern colloidal chemistrythat the precise conditions under which adsorptionoperates have been defined. Kaolin, for example,which consists mainly of Si02, has powerful andvery general adsorptive powers, particularly in anacid medium. (In alkaline media it is almostinactive and the elution of already adsorbedmaterial may even be brought about by alkali.)It is argued that such a material taken by mouthshould serve to remove " bacterial toxins " andother undesirable toxic matter from the intestinalcanal; but if we stop to define the terms of theargument we find ourselves asking, What are thebacterial toxins in question ? What part do theyplay in the production of disease ? Do they infact exist ? To none of these questions has asatisfactory answer yet been given, and as Dr.E. S. EMERY of Boston says in his excellentreview,1 "the physician who uses adsorbents is

entering a field of therapeutics in which the pit-falls are not clearly indicated and the usefulnessof which has not been definitely defined."Powerful adsorbents such as kaolin are double-

edged weapons, and in our efforts to combat thestill quite hypothetical condition of " alimentarytoxaemia" we are introducing substances thatalmost certainly will exercise their adsorbent

capacity indiscriminately on enzymes, mucus,

foodstuffs, and vitamins, and so interfere in anunpredictable way with the delicate mechanismsof nutrition. Further we must remember thatwe are administering a material which ordinarysense suggests is unsuited to the digestive apparatus;it is abrasive and completely non-digestible, andit is capable of forming insoluble concretions inthe body. It is possible moreover that it may bephagocytosed or otherwise lodged in the cells ofthe alimentary tubes. Be this as it may, EMERY

points out that kaolin has not escaped criticismin actual therapeutic use. Intestinal irritationand inflammation, partial intestinal obstruction,

I

and even perforation have been ascribed to kaolintreatment, and HoELZEL has reported the pro-duction of intestinal polyposes in rats by treat- I

ment with large doses. Even these considerations i

by no means exhaust the difficulties. Such precise -knowledge as we have of the process of colloidaladsorption is based on the study of comparativelysimple systems in vitro, and from this knowledgeit would be impossible to predict what will happenin the complex and changing environment of the (

alimentary canal, where the hydrogen-ion con- centration is variable, and where there are so

many substances, useful and useless to the body i

competing for adsorption. There is the furtherdifficulty that adsorbing agents can only be kept t

in a state of maximum activity under carefully :3arranged conditions ; they readily adsorb gases, &c.,

-

1 J. Amer. med. Ass. Jan. 16th, 1937, p. 202.

and so have their adsorptive activity destroyedor impaired. One might ask, for example, how fartheir efficacy is affected by any liquid such as oilwhich may be used as a suspension medium.The question of the action of adsorbents on the

intestinal flora is an interesting one, and lendsitself to precise study. BRAAFLADT in 1923 notedthat kaolin will adsorb and inactivate large quan-tities of bacteria. Dr. W. SMITH, on p. 438, describeshow he has investigated in vitro the action ofadsorbents on the flora of the human faeces, andhas found that kaolin and in particular kaolin-alumina mixtures, if given in adequate quantities,remove bacteria, including Bacterium coli almost

entirely from suspensions of faeces, as judged byplate-counts of the faeces before and after adsorp-tion. This is in itself an interesting observation,but it must be related to BRAAFLADT’s statementthat in the living human being kaolin treatmentbrings about a change from a proteolytic to anaciduric intestinal flora. Allowing that Bact. coli

may be suppressed, or replaced by an acidophilicflora in the living subject, it by no means followsthat any good has been done by the process. Sofar as we know we have lived on relatively goodterms with our intestinal flora for countless

generations and to any one impressed by thebeautiful equilibria of the normal human body itwould seem unwise to interfere with them withoutdue forethought. That we are being constantlypoisoned by our intestinal contents is one ofthose largely irrational beliefs that must have itsroots deep in human nature. The address by Prof.WITTS at the front of our present issue is one thatwe are especially glad to publish because he is

attacking one of the major errors of current

practice.MINERVA

WE have before us 1 in one volume the directoryof universities and professional schools in everypart of the world, compiled by Dr. Gerhard Ludtkewith editorial guidance from Dr. F. Richter. For

thirty editions this Yearbook of the Learned Worldcontained within the same cover not only this informa-tion, but similar details of research institutes,observatories, libraries, archives, museums, andmuch else. Running, as it did, to 4345 pages,it had to be bound in three volumes, with consequentloss of some of its time-honoured ease of reference.The editors of Minerva then decided to carry throughthe cleavage, with the result that the more mobilepart of the learned world has its own section whichhas been kept up to date and reissued at shortintervals. That is a great convenience for all whohave occasion to identify the position of some memberof a teaching school in a university or medical schoolhowever remote. There is rather a disturbingdoubt expressed in the preface whether it is physicallypossible to bring together and to revise such wide-spread material ; but it has been done, and its successis a testimony to the publisher’s love of science ingeneral and of this task in particular. We are gladto recognise the public spirit of those who haveagain produced such a worthy book.

1 Minerva : Jahrbuch der Gelehrten Welt. 32nd edition.Section : Universities and High Schools. Berlin and Leipzig :Walter de Gruyter and Co. 1936. Pp. 2201. RM.48.