THE NORMAL HUMAN COLON

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Mr. JOHN MACDONALD, discussing racial problems in the southern United States, said that Negroes constituted only 10% of the population. In some States, however, the proportion was as high as 40%, and it appeared that racial intolerance became maximal the more nearly a 1:1 ratio was approached; each group then experienced the maximum of insecurity, and violence was apt to break out. Violence was also common after large Negro demonstrations, probably because of accentuation of the feeling of insecurity amongst Whites. Factors tending to diminish violence included a common culture-Negroes felt themselves to be true Americans and had no wish to return to Africa; they merely wanted America to extend to them the principles of the Constitution which applied to other Americans. The area of conflict was therefore limited. There was also a strong tradition of non-violence amongst Negroes deriving in part from the Christian ethic, and, as the U.S. Government supported their claim for civil rights, non-violent tactics and legalistic methods had proved more useful than would be the case where Governments were strongly antagonistic. There was a section which did advocate violence and which seemed to be growing; this might be regarded as a warning not to delay too long the issue of equality. But, with Negroes constituting so small a proportion of the population, the majority were aware that violence was unlikely to succeed; they hoped to improve their political and economic status without resort to violence, and probably would be able to do so. up, Dr. NORMAN MACDONALD said that we faced with two explosions: (1) the nuclear explosion, and (2) the population explosion. The first could be regarded as due to man’s aggressive instinct getting out of control, and the second as the result of not being able to limit the consequences of the sex instinct. It could be that the one was the crude answer to the other, but this we could not and should not accept. In man the aggressive instinct operated mainly constructively, enabling him to establish himself as an individual who could make his own contribution to the maintenance of society. When diverted from normal channels by the closure of satisfactory outlets, however, aggression could become highly dangerous, especially in present circumstances. Clearly for the future we had to think in terms of the welfare of mankind as a whole. While the world in general lacked a unifying faith, in medicine we were especially privileged to possess one whose avowed objective was to help mankind by conquering and preventing disease of all kinds. The application of this ethic needed to be expanded in medicine itself and also in other spheres of science. But the existence and recent rapid growth of research into methods of promoting biological and chemical warfare was a grave contravention of the principle embodied in the Hippocratic oath. Moreover, its consequences were unforeseeable, for any country with the necessary laboratory facilities could carry out this type of research and adequate inspection was impossible. No doubt those engaging in such research did so because they thought that by so doing they were defending their country; but defence by such methods was likely to have consequences for all countries which could not be contained. Only in our intellects and in our intentions was there any true defence. If outlets for constructive human activity were to be provided by advances in knowledge, we should have to adhere to the Hippocratic oath and its modern equivalent in the Declaration of Geneva adopted by the World Medical Association in 1948. International cooperation in the medical field was an urgent priority.

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THE NORMAL HUMAN COLON A SYMPOSIUM on the Anatomy, Physiology, and Pharmacology of the Human Large Intestine was held at St. Mark’s and the Central Middlesex Hospital on July 10 and 11. About 70 participants with different interests attended and it became clear that new knowledge on the structure and function of the colon is rapidly being accumulated. Much of the programme was devoted to the structure, innervation, and action of colonic muscle. I. P. WILLIAMS has shown by dissection that the circular muscle forms an interlinked mesh, attached to the longitudinal taeniae, the mesh structure enabling it to expand or contract as the length of the colon alters. Two groups of workers have been studying the pharmacological reactions of isolated muscle strips in vitro. AUDREY BUCKNELL and B. WHITNEY, using strips of longitudinal muscle, have shown that the major nervous impulse appears to be adrenergic and to cause the muscle to relax. It has been possible to demonstrate only a weak cholinergic contraction. D. FISHLOCK and A. G. PARKS, using circular muscle strips, have made similar observations. They have also studied the effects of histamine and 5-hydroxytryptamine. Both seem to act directly on the muscle-fibre. The effect of histamine is variable, the usual response being relaxation followed by contraction on washout of the bath. Serotonin appears to have different effects in different parts of the gut, causing contraction of ileal muscle, relaxation of muscle from the sigmoid colon, and contraction of the internal sphincter ani. The ascending colon is relatively insensitive to the drug and gives a less consistent relaxation than the left colon. A similar difference between the right and left colon has been observed independently in vivo by MARIA RAMORINO, and also by J. J. MISIEWICZ, who have found that the right colon shows increased activity whereas the left colon shows decreased activity in response to injected serotonin. I. DAWSON showed that cholinesterase in ganglion cells may be demonstrated histochemically and similar techniques may provide a further method of study. One of the problems in studying colonic motility in vivo is to know whether the muscular activity is intrinsic or arises primarily in response to nervous stimulation. A. M. CONNELL, studying patients with spinal-cord lesions, has shown that colonic muscular activity tends to be intense and irregular when the lower spinal cord is destroyed, suggesting that nervous impulses have an inhibitory function, and thus adding support to the pharmacological observations already described. E. N. ROWLANDS made the point that most contraction waves in the colon are of a delaying or segmenting type, and peristaltic waves G. M. ARDRAN and J. RITCHIE showed an are rarely seen. interesting film of these segmenting movements occurring in the sigmoid colon. D. A. W. EDWARDS suggested that the primary factor in movement of the colonic contents may be an induced relaxation of the muscle abolishing the delaying waves and allowing forward flow. There was considerable discussion on mass movement in the colon and on the colonic folds seen radiologically. E. N. ROWLANDS reviewed older descriptions of mass movements in the colon, observations now unlikely to be repeated in view of modern knowledge of irradiation hazards. Such movements have not been described frequently, and it is not clear whether they are a usual mechanism of colonic transport or perhaps a fortuitous happening. All the evidence suggests that movement of colonic contents is imperceptible to the hepatic flexure. When mass movements do occur they involve the transverse and left colon, the first event being disappearance of haustra followed by rapid synchronous contraction of a considerable length of bowel. J. HALLS has recently developed an ingenious technique for observing the passage of different sized radio-opaque markers through the colon. He has not been able to demonstrate any movement of colonic contents associated with the urge to defalcate, except that in one subject there was reflux from the rectosigmoid to the descending colon when the urge was resisted. The extent of the bowel cleared at defalcation varies widely in normal subjects, some-

203 times the rectum alone being partly emptied and sometimes the whole left colon up to the splenic flexure; the proximal bowel contents are undisturbed. A. YOUNG showed that folds demonstrable in the atropinised colon distended with air tend to be constant in one subject over many months. Other wider folds appear to be the result of muscular contraction and vary from time to time. It was suggested that the " fixed " folds are anatomical structures, consisting of a double layer of mucosa bridged by the serosa. The disappearance and reappearance of these folds in certain diseases cannot yet be explained. Further information on innervation of the colon may be derived from a study of colonic reflexes. J. J. MISIEWICZ showed that an increase in muscular activity tends to occur on both the right and left sides of the colon after food, though this response is not invariable and the two sides of the colon may react differently. In other studies, A. M. CONNELL has shown that this response may occur at the sight of food, not only in normal subjects, but also in patients with transection of the spinal cord. In view of these observations, the term " gastrocolic reflex " is perhaps a misnomer as the stomach may not be involved, and the reflex nature of the response has not so far been demonstrated. Other reflexes which evoked much discussion are those concerned with defalcation. N. PORTER discussed the reflexes concerned with contraction and relaxation of the external sphincter ani. This sphincter shows tonic activity, maintained by a stretch reflex mechanism, which is augmented by movements such as coughing and inhibited by distension of the rectum. A. YOUNG has observed that filling of the rectum with barium tends to cause contraction of the pelvic colon, suggesting a reflex preventing reflux of colonic contents during defalcation. J. RITCHIE has noted that contraction of the sigmoid colon may be associated with relaxation of the anal sphincter. I. KELSEY FRY suggested from cineradiographic observations that contraction of the upper rectum and sigmoid may be induced by stimuli from the anus, a hypothesis supported by the use made of digital stimulation of the anus by paraplegics to induce reflex defalcation. Factors concerned in continence were discussed by several speakers. N. PORTER considered that pressure within the anal canal at rest is largely due to tonic concentraction of the internal sphincter. H. L. DUTHIE came to a similar conclusion when he investigated the effect of muscle relaxants on pressures within the anal canal. D. A. W. EDWARDS showed that the anal sphincters are incapable of withstanding the prolonged and high intra-abdominal pressures which may develop during somatic movements. He advanced evidence suggesting that the high pressure itself, acting on the outside of the closed sphincteric segment, is a major factor in maintaining continence. H. L. DUTHIE has investigated sensation within the anal canal and shown that the lower part only of the canal is sensitive to touch. This area is usually protected by contraction of the sphincteric segment but may become exposed to the rectal lumen when the rectum is distended. B. CREAMER discussed the turnover of colonic epithelial cells, showing that cell division tends to occur in the lower two-thirds of the crypts, most of the cells then migrating to the surface and being shed into the lumen. The histochemical characteristics of these cells change as they migrate, and I. DAWSON showed that certain enzymes can be demonstrated only as they approach the surface. The concentration of electrolytes in fsces was discussed by 0. WRONG. Both he and

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This symposium showed the active interest that is being taken in the colon by workers in different branches. The most rapid advance at present seems to be in our knowledge of pharmacological reactions, in vitro and in vivo, and interesting developments which will add greatly to our knowledge of the innervation and activity of the gut are

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Parliament The Ministry and the Pharmaceutical Industry THE Ministry of Health and the Association of the British Pharmaceutical Industry have agreed on a new scheme for the regulation of drug prices, which will have effect for three years from July 1, 1964, and thereafter is subject to six months’ notice by either side. The new scheme is on the same general lines as the earlier one, but there are a number of important modifications. The scheme has been extended in scope to include all medical specialities prescribed by general practitioners instead of rather less than nine-tenths as formerly. The importance of research is recognised by two changes: an increase from three to four years in the period of freedom from control for preparations resulting from substantial and original research, and a reduction to two years of the free period for other preparations; and a specific allowance for research in the calculation of the maximum prices of preparations other than those which qualify for the export criterion. The scope for direct negotiation at the Ministry’s option in relation to widely used drugs qualifying for the export price criterion has been extended in two ways: first by a reduction of the limit at which the option may be exercised in the case of patented preparations, and second by the introduction of a new option at a lower limit in respect of unpatented preparations marketed in competition with exact unbranded equivalents. There is provision for retrospective adjustment in certain cases. The new scheme, like its predecessors, provides that the price of any preparation outside the free period should not be increased without the approval of the Ministry. The Association has agreed to use its good offices with its members to ensure the prompt submission of all relevant information necessary for the purpose of negotiations under the scheme. QUESTION TIME

Hospital Building Programme Mr. L. A. PAVITT asked the Minister if he would give the financial content of the hospital building programme as approved in the revision published in April, 1963, and the content now proposed in this year’s review for each of the hospital regions.-Mr. BARBER replied: For 1963, E600 million. The E750 million of this year’s review, adjusted to an income and expenditure basis and including the value of centrally purchased equipment, is allocated as follows:

R. SHIELDS, using a perfusion technique, have shown independently that sodium is absorbed from,and potassium secreted into, the lumen by the colonic epithelium, the changes being

increased by aldosterone. C. EDMONDS drew attention to the difficulties of interpreting perfusion data concerning potassium because for this ion the two-compartment hypothesis does not hold for short-term experiments. Of special interest to surgeons were papers by J. D. GRIFFITHS and A. G. PARKS on the blood-supply to the colon. J. E. LENNARD-JONES, describing a survey of bowel habit in an industrial population, showed that 99 °o of the subjects studied

General Practice in the Highlands and Islands Sir JOHN MACLEOD asked the Secretary of State for Scotland whether he was aware of the special difficulties of general medical practitioners in the Highlands and Islands; and what action he proposed to take.-Mr. MicHAEL NOBLE replied: As an immediate measure, I have increased the net income yard-