866

Fig. 2.

With this unit hypothermia has, on some twenty occasions,been induced and maintained for between 30 and 105 hours.Induction in some patients has been achieved in 11/2 hours, butmostly it has taken over 2 hours. We consider that this dis-advantage is more than compensated by the absolute simplicityof the apparatus, with no complex working parts which

require servicing, and by the ease of handling. Moreover, forthose conditions in which it may be necessary to prolong hypo-thermia for several days it is of little importance that inductionof hypothermia should take half an hour more or less, but it isof considerable advantage to be able to maintain that hypo-thermia with little difficulty or inconvenience.The cooling of two patients at the same time is achieved by

leading the waste water from the mattress (at 7-10°C) througha separate cooling unit (coil D in fig. 2) placed in the same ice-bin, and then around a second mattress. This has been

entirely successful in practice; in fact the temperature at thesurface of the second mattress is usually below that of thefirst mattress. The rate of tap-water flow for this arrangementis retarded as a result of the combined resistance of the tubingforming the four copper coils, the two mattresses, and thejoining tubing, and it measures as little as 10 gallons per hour.Alternatively, when cooling only one patient, the two mattressesmay be used together, above and below the patient, therebyreducing the time for the induction of hypothermia.The price of 3/8 in. gauge copper tubing is 30s. 6d. per 25 ft.

To form the helix the copper tubing may be wound aroundany suitable " former "-an old metal pipe or a lump of wood-which is later removed.The cooling mattresses may be obtained from Capon Heaton

& Co. Ltd., of Birmingham, at C10 each or E29 for a set ofthree. They are constructed to withstand pressures of up to5 lb. per sq. in. During changes of posture and inadvertentfolding of the mattress, double these pressures may be reached.To prolong its period of usefulness it is important to insert atthe inlet side of the mattress a valve set to open at pressuresexceeding 5 lb. per sq. in.

Broken ice, delivered as necessary, may be stored con-

veniently in a large domestic dustbin, which is mounted on

Fig. 3.

castors and placed close to the plastic bincontaining the cooling unit.The total cost of the complete unit con-

taining one mattress is about E26.We wish to thank Staff-nurse G. Anvar, s.n.x.,

for her many helpful and practical suggestions;Miss June Akister, medical artist, for the diagram;Mr. E. G. Johns, hospital engineer, for kindlyarranging to make the copper coils; and the

photographic department of the Royal MarsdenHospital, for the photograph.M. B. is in receipt of a grant from the British

Empire Cancer Campaign.MAURICE BLOCH

M.B. Lond.Clinical Research Assistant

Department of Neurosurgery,St. George’s Hospital,

London, S.W.1

H. B. EDGEHILLM.B. Lond., D.A.

Anæsthetics RegistrarRoyal Marsden Hospital,

London, S.W.3

Medical Societies

OPHTHALMOLOGICAL SOCIETY OF THE

UNITED KINGDOM

THE 83rd annual congress of the OphthalmologicalSociety of the United Kingdom was held in London onApril 3-5. The two principal subjects were HypertensiveRetinopathy and the Indications for Glaucoma Surgery.

Hypertensive RetinopathyProf. J. McMICHAEL remarked on the improved prognosis

associated with new methods of treatment and with assessment

by retinal photography. Serial photographs demonstrated howsoft exudates appeared and grew rapidly, and might continue toappear for some days after the blood-pressure had been

lowered, their growth often seeming to be constrained by theadjacent vessels-which they might even press temporarilyaside until the exudation started to regress. Later these softexudates became granular, resembling hard exudates, whichindeed generally appeared at about this stage, unrelated in theirsite either to the soft exudates or to haemorrhages, and taking upto a year to resolve (unlike the soft exudates or hxmorrhages,which resolve in a few weeks). The change in the blood-vesselswas much less striking, and the arterial narrowing rarely alteredafter hypotensive therapy, indicating that this narrowing wasanatomical rather than functional.

Mr. D. W. HILL described his measurements of the calibre ofthe retinal arterioles. The response to a fall in blood-pressurewas variable and occurred in about half the cases, with a reduc-tion in calibre of the large arterioles and a distinct increase inthat of the small arterioles.

Dr. JOHN HARRY described an investigation at present beingcarried out in the pathology department of the Institute ofOphthalmology on eyes from cases of malignant hypertensionBy a new technique the fundus lesions detected in life couldbe exactly located in the postmortem specimen. Vessels whichhad been unduly narrowed in life were serially sectioned; themajority showed diffuse hyperplastic sclerosis, but this appearedto be consequent upon pre-existing hypertonus. Dr. Harryagreed with the view previously expressed by Leishman thatthe effect of hypertension on retinal vessels depended not onlyon the benign or malignant course of the disease, but also uponthe degree of involutionary sclerosis present in the vessels atthe onset of the hypertension.

Prof. NORMAN ASHTON described the pathology of " cotton-wool spots " in malignant hypertension and other diseases asrevealed in injected and digested specimens. Capillaries ButhjRthe oedematous focus were uninjectable, being obliterated hthe tissue pressure, whereas the immediately adjacent cjpli-

867

laries were dilated and often showed microaneurysms. Hyalineand lipid changes, typical of so-called " fibrinoid necrosis ",were commonly to be found in the terminal and precapillaryarterioles supplying the affected retinal area; in malignanthypertension this was apparently the cause of the " cotton-wool spot". The nature of cytoid bodies found aggregatedwithin the swollen nerve-fibres had long been an enigma.Professor Ashton had examined them with the electron micro-

scope and concluded that they were terminal bulbous swellingsof ruptured axons corresponding to Cajal nodes. The cyto-

plasm consisted of large numbers of swollen mitochondriawith numerous vesicles and granules lying in a filamentarybackground; it was probably formed by axoplasm. The

pseudonucleus on the other hand was distinct from the axo-plasm and consisted of a heterogeneous mass of poorly resolved,ill-defined particles of high electron density lying within theaxoplasm; it was not a nucleus, but its true character was stillobscure.

Dr. C. T. DOLLERY described a new technique by whichthe retina was photographed at intervals of a few secondsafter an intravenous injection of fluorescein. This demon-strated a streaming within the larger vessels and made it

possible to see vessels too small to be seen with ordinary light.In hypertensive patients the clusters of microaneurysms, whichProfessor Ashton had demonstrated around the soft exudatesin the postmortem eye, could be seen developing, and oftendisappearing when the hypertension was treated. The leakageof fluorescein in the neighbourhood of exudates, and otherkindred changes, were all displayed.

Indications for Surgery in GlaucomaDr. PAUL CHANDLER (Boston, Mass.) said that in his opinion

operation was indicated in nearly all cases of angle-closureglaucoma. After an acute attack in one eye a peripheraliridectomy should be performed on the fellow eye if the angleof the anterior chamber was very narrow. Even in the presenceof peripheral synechioz, peripheral iridectomy alone oftensufficed to control the tension. If more than a third of the

angle was closed by synechix a filtering operation was generallydesirable, especially if there was cupping of the optic disc.Dr. Chandler emphasised the value of gonioscopy at

operation, the aqueous first being tapped off and the anteriorchamber then overfilled with saline to give a better view ofthe angle.Prof. G. I. SCOTT (Edinburgh), discussing simple glaucoma,

stressed the importance of visual-field examination and theappearance of the optic discs as a guide to effective treatment.In his view the modern range of medical treatments tended to

encourage procrastination, and he gave evidence that surgerywas more effective in delaying the progress of the disease ifundertaken in the relatively early stages. In the late stages,where the visual field was severely curtailed, surgery, althoughapparently successful in controlling the tension, was oftenfollowed by further progressive loss of visual field. Further-

more, for surgery to be effective, it should be done before thearcuate scotoma broke through to the periphery. ProfessorScott was in favour of surgery in cases where there was cuppingof the discs and visual-field loss with " normal " tension. Hestressed the importance of the timing of surgical intervention:the choice of operation was, he felt, a matter for the individualsurgeon.

Mr. A. J. B. GOLDSMITH considered secondary glaucoma.In general, management depended on the aetiological factorsand on assessment of the difficulties of aqueous drainage.Regarding inflammation, secondary glaucoma due to chronicuveitis was a more difficult problem than that associated withacute uveitis. In the Posner-Schlossmann syndrome (glauco-mato-cyclitic crises) surgery was rarely indicated. Causes ofglaucoma due to trauma were considered under two headings:contusion and perforating wounds. These cases were oftencontrolled medically. There were many conditions of the’ens which gave rise to glaucoma, the majority needingoperation.

Reviews of Books

A Short History of Medicine2nd ed. CHARLES SINGER and E. ASHWORTH UNDERWOOD.Oxford: Clarendon Press. 1962. Pp. 854. 63s.

" THE position that Medical Science has now assumed ",said Charles Singer thirty-five years ago, " demands that alleducated men and women should have some knowledge of thesubject." And, because he felt that such knowledge could bestbe imparted by recapitulating the steps by which it had beenestablished, he wrote his Short History of Medicine. The

clarity and attractive style of this book made it one of the mostpopular of its kind ever published. In particular they earned ita place in many school libraries, where it introduced more thanone prospective doctor to his profession.

After this first appearance in 1928, the volume was oftenreprinted, but was never amended at all extensively. NowDr. Ashworth Underwood, with the assistance, until his

death, of the original author, has completely revised it. In

doing so, he has fitted Dr. Singer’s book for a new role. Witha threefold increase in size (the number of pages has doubled,and the type used is smaller), the work has passed from therealm of the general reader and of the student beginningmedicine. But the undergraduate well advanced in his training,and the doctor with a historical bent, have been provided withan excellent text, intermediate between outline surveys of the

subject and specialised monographs. It is in those chaptersdescribing scientific progress during the past century that themost substantial additions have been made. These must havebeen difficult to write, for they are often concerned with

highly technical researches. Such steps as those which led tothe demonstration of exo-erythrocytic malarial parasites (tocite only one example) are analysed so clearly that they will be ofgreat interest even to those experienced in tropical medicine.Other readers will find several famous discoveries reviewed in atruer perspective than hitherto; so that some may be surprisedto realise that Semmelweis was certainly not the first to showhow puerperal fever was spread and could be prevented; thattuberculosis had been experimentally transmitted to animals,and a distinction made between its human and bovine forms,almost twenty years before Koch’s publications; and that thecontribution made by Pravaz towards the invention of thehypodermic syringe, with which he is so often credited, was infact negligible. Dr. Ashworth Underwood is to be congratulatedon the way he has discharged a very responsible task, and onthe production of a worthy successor to that notable firstedition.

Comparative NeuropathologyJ. R. M. INNES, SC.D., D.SC., PH.D., M.R.C.V.S., F.R.S.E., pathologist,biology department, Brookhaven National Laboratory, Upton,New York; L. Z. SAUNDERS, D.V.M., school of veterinary medicine,University of Pennsylvania. New York and London: AcademicPress. 1962. Pp. 839. 229s.

IT will be decades before we can learn if there are

diseases of the hypophysis peculiar to the echidna and ifchameleons are especially prone to chemodectomas. Indeedwe know next to nothing of the neuroanatomy of most creaturesin the animal kingdom, let alone any neuropathology. Thereason for this ignorance is, of course, economic, and the manylacunas in this book make it clear that the knowledge we have islargely determined by agricultural and public-health demands.Much information has already accumulated about neurologicaldiseases of domestic and other animals under observation, andgood use has been made of animal patients and pathologicalmaterial in zoos, although few zoos are sufficiently well endowedto provide research facilities.

This book is fascinating reading for the " human " neuro-logist and pathologist, who may not have had opportunity tostudy such entities as the Aleutian disease of mink,

" old dogencephalitis ", dumkoller of horses, the choreic syndrome ofbaboons, fainting in foals, and the paralytic syndrome of coon-