- Email: [email protected]
HEALTH CARE IN SOUTH AFRICA
95 posts. Recognition of posts for higher medical training will usually be made at senior-registrar level. The number of these posts is related by the Departments of Health to the anticipated number of consultant vacancies, but a small number of registrar posts may be considered for recognition, provided that the training programme available meets the necessary requirements for the specialty as described in the First Report, published in October, 1972. Joint Committee on Higher Medical Training, Royal College of Physicians, 11 St. Andrew’s Place. London NW1 4LE.
CYRIL A. CLARKE, Chairman, Executive Committee.
detects
polysaccharide produced by pathogenic pneumopolysaccharide derived from pharyngeal
cocci and not commensals.
known to have received prior antibiotic was detected in all 5 purulent sputa obtained from these 6 patients, in 5 urine samples, and in 3 sera; antigen was also detected in the pleural fluid of 4 of 6 patients who developed sterile pleural effusions whilst receiving antibiotics. C.LE. thus provides a rapid method for establishing an aetiological diagnosis in most patients with pneumococcal pneumonia and is little affected by prior antibiotic 6
patients
treatment.
were
Antigen
treatment.
BACTERIOLOGICAL FINDINGS IN PNEUMONIA
SIR,—Dr Spencer and Dr Philpand Dr Kinnell2 have raised some important points in regard to the bacteriological diagnosis of primary pneumonia. Dr Kinnell stresses the importance of accurate bacteriological diagnosis in view of the fact that penicillin-resistant organisms such as Staphylococcus aureus can produce classical lobar pneumonia. Sputum culture is, however, often unrewarding. Dr Kinnell isolated a potential pathogen from only 24% of sputa examined; Dr Spencer and Dr Philp isolated pathogens from a much higher proportion of untreated patients but obtained pathogens in only 31 % of the 52 of their 76 patients who had received some treatment before sputum culture. We are particularly interested in these observations since lobar pneumonia is the commonest cause of medical admission to the adult medical wards at Ahmadu Bello University Hospital, Zaria. We feel that sputum culture is of little value in the investigation of suspected pneumococcal pneumonia, as commensal pharyngeal pneumococci have been isolated from the upper respiratory tract in up to 60% of normal people,3and it has been reported4 that Streptococcus pneumonia failed to grow in over 40% of sputum samples in which numerous gram-positive diplococci were seen on direct smear. Str. pneumonia is isolated from the blood in only about a third of patients with pneumococcal pneumonia even when guineapig inoculation is carried out.5 Bacterial polysaccharide antigens can readily be demonstrated in biological fluids by counterimmunoelectrophoresis (c. I.E.); and pneumococcal antigen has been detected in the blood of patients with pneumococcal pneumonia, using C.LE.6,7 We have therefore carried out a prospective study of the value of C.LE. in establishing a bacteriological diagnosis in pneumonia (unpublished). 98 patients with radiologically proven lobar pneumonia were studied. C.LE. was carried out with pneumococcal antisera obtained from the Statens Seruminstitut, Copenhagen. Pneumococcal antigen was detected in 42 (79%) of 53 purulent sputa, in 42 (54%) of 78 urine samples, in 26 (27%) of 98 initial serum samples, and in 10 (83%) of 12 pleural effusions. In contrast, pneumococcal antigen was detected in only 3 of 40 purulent sputa from patients with pulmonary tuberculosis and in none of their serum or urine samples. The serotype of the pneumococcal polysaccharide present in sputum was identical with that found in the blood or urine in all but 1 of the 29 patients with lobar pneumonia investigated; this suggests that c.i.E. of the sputum only 1. 2. 3. 4. 5. 6. 7.
Spencer, R. C., Philp, J. R. Lancet, 1973, ii. 349. Kinnell, H. G. ibid. p. 919. Laurenzi, G. A., Potter, R. T., Kass, E. H. New Engl. J. Med. 1961, 265, 1273. Fiala, M. Am. J. med. Sci. 1969, 257, 44. Mufson, M. A., Chang, V., Gill, V., Wood, S. C., Romansky, M. J. Am. J. Epidem. 1967, 86, 526. Dorff, G. J., Coonrod, J. D., Rytel, M. W. Lancet, 1971, i, 278. Kenny, G. E., Wentworth, B. B., Beasley, R. P., Foy, H. M. Infect. Immun. 1972, 6, 431.
Department of Medicine, Ahmadu Bello University Hospital, Zaria, Northern Nigeria.
PETER TUGWELL BRIAN M. GREENWOOD.
FIBRE AND OBESITY
SIR,-Those of us who spent our professional lives in tropical Africa would like to express agreement with the suggestion of Dr K. W. Heaton (Dec. 22, p. 1418) that food fibre has an important role in preventing obesity. Personal observation can report that obesity was very rare in all East Africans in 1929 but became very common and often severe in upper socio-economic groups in 1950-70. In 1929 Africans ate a large amount of unprocessed carbohydrate foods, maize meal, millet meal, potatoes, plantains, and beans. No white wheat flour or white rice were eaten, and very little, if any, sugar, for local production had only just started. Apart from a few pastoral tribes, little milk and no butter were taken and no vegetable oil outside the coastal strip; margarine was unknown among them. Unprocessed groundnuts were almost the only source of vegetable fat, which like carbohydrate is formed with the plant cell wall of fibre. Africans took very little animal fat, for the wild animals and their domesticated goats, cattle, and sheep had little obesity or fat in their carcasses.
Many envisage plant fibre as a minute portion of our vegetable foods, for white flour contains crude fibre 0-1%. The unavailable carbohydrate and lignin, or dietary fibre, Wheat wholemeal as some are calling it,! is far larger. contains 10% of dietary fibre, celluloses 4%, hemicelluloses 6%.2 Fibre is an important constituent of the normal But neither the word fibre nor unavailable carboreceives much discussion in any book on obesity. Diabetes is a disease of carbohydrate metabolism and carbohydrate is formed within a vegetable cell wall of fibre, but the word fibre does not occur in the index of any journal specially devoted to the study of diabetes, and this disease was rare in East Africans in the 1930s.4
diet.3
hydrate
Woodgreen, Fordingbridge,
HUGH TROWELL.
Hants.
HEALTH CARE IN SOUTH AFRICA
SIR,-This is in reply to a comment by Dr Goodall (Dec. 22, p. 1436) on the thoroughly investigated and incisive paper somewhat critical of the health-care delivery to Blacks and Asians in South Africa. This paper has been labelled as political " by the commentator, after citing many achievements of South African equalisation of the quality of medical care, such as availability of all medicines to all people and an infant-mortality rate " appreciably less " disastrous than the worst in the world. I feel that considering the grossly discriminatory distribution "
1. 2. 3. 4.
Southgate, D. A. T. Plant Foods for Man, 1973, 1, 45. Fraser, J. R. J. Sci. Fd Agric. 1958, 9, 125. Cummings, J. H. Gut, 1973, 14, 69. Trowell, H. Non-infective Disease in Africa; p. 306. London, 1960.
96 of medical care and its quality in South Africa the situation there requires not only medical exposing but it is also in need of intensive political work and one can but congratulate The Lancet for the courage to enter a medicopolitical scene, so gravely neglected by the medical profession. To abrogate this political stance in favour of " pure science ", precluding any bias and political opinion, is in my opinion neglecting an important duty of all physicians. Attention to the distribution of health care and its quality, affecting all people, has been neglected by the medical profession in a rather self-seeking way. Medicine, dealing with people, is intrinsically political and we should recognise that, whether we want it or not, we will have to enter that arena. 55 East
Washington Street, Suite 2801,
ERIC C. KAST.
Chicago 3, Illinois.
MEDICAL/INDUSTRIAL
COMPLEX
SIR,-A correspondent writing in your " Round the World" column (Dec. 15, p. 1380) describes the U.S. medical/industrial complex " and refers to a series of articles in the New Yorker. His general description of the problem is fairly accurate and there is little doubt that in the field of occupational health the U.S. has lagged far behind Europe. That much of this is a consequence of pernicious behind-the-scenes lobbying, and of suitably large contributions to the election campaign funds of certain politicians, is beyond doubt. But as one who has been in occupational medicine for several years, and who can also claim to belong to the one organisation-namely, the National Institute of Occupational Safety and Health"
of Brodeur’s New Yorker diatribe with I feel that Brodeur grossly overstates much of his case. His description of the asbestos exposure incident in Texas is unfortunately only too true, but he then went on to "question the motives of all those who recommended a 5 fibre " asbestos standard. In doing so he implied that some of the most respected names in American and Canadian medicine, men with international reputations, were influenced by the fact that they were retained as consultants by industry. Many of those on whom such aspersions were cast are academicians, and as such precluded from receiving any It might be financial remuneration for their services. difficult for Brodeur to accept, but some companies are concerned about their employees and are willing to seek expert advice to see whether an industrial hazard exists. There are those who might be pardoned for thinking that Brodeur relied too much on the accuracy of the material that was given to him by some of the " heroes " of the New Yorker articles. In this regard, both labour and management have in the past contracted with certain groups (and doubtless will do so again) when they have been faced with occupational health problems. Unfortunately, too often the choice of contractor has been predicated on the contractor’s political sympathies rather than on his medical and scientific competence or on his objectivity. Let it be recognised that both management and labour have axes to grind, as witnessed by the recent support given by the combined labour/management asbestos lobby to those studies purporting to show that fibreglass is as dangerous as asbestos. Meanwhile, the one disinterested and impartial group, the National Institute of Occupational Safety and Health, is unable to assume all of its responsibilities owing to lack of staff.
that came colours still
out
flying, albeit a little tattered,
Department of Medicine, West Virginia University, Medical Center, West
Morgantown, Virginia 26506,
U.S.A.
W. K. C. MORGAN.
ROSETTING TESTS SIR,—MISS ilrvine and Dr cooper (.uec. , p. i440) report that identification of B and T cells among human peripheral blood lymphocytes may be unreliable if the samples have been stored for even a few hours before examination. Experience in this laboratory suggests that with appropriate techniques the effects of storage can be minimised. The proportion of peripheral blood mononuclear cells forming spontaneous rosettes with sheep erythrocytes (presumptive T cells) is, in our hands, 52-75% (mean 62%) in samples from healthy adults under conditions of normal daily activity. 1,2 These figures agree well with those recorded in a number of centres 3-8 but contrast with a mean value of less than 30% obtained by Irvine and Cooper and by some other groups.7-9 Among variable factors in the technique which may account for the discrepancy, the most critical appears to be some individual property of the sheep from which erythrocytes have been obtained.1 The period of incubation of the lymphocyte/erythrocyte mixture before counting rosettes is, however, also important, reproducibility of the counts increasing with prolonged incubation. One reason for this may be that deleterious effects of storage of the blood sample are slowly reversed when the lymphocytes are suspended in culture medium, as the following experiment suggests. Defibrinated blood samples from four healthy adults were each divided into two aliquots, one of which was processed immediately and the other held for two hours at room temperature before proceeding. Mononuclear cells separated from the samples by centrifugation over a ’Ficoll/Triosil ’ layer 10 were washed, resuspended in Ham’s‘ F10 ’ medium with 20% fetal calf serum, mixed with erythrocytes from a selected sheep, and spun down at 50 g for five minutes. Rosettes were counted (in triplicate samples) after one hour’s incubation of the lymphocyte/ erythrocyte mixtures at room temperature. In every case the stored blood had a lower percentage of rosette-forming cells (R.F.C.) than the corresponding fresh sample (mean values 58-1% and 63-2%, respectively). When counts were made on additional (triplicate) mixtures which had incubated overnight at room temperature the difference had disappeared and in two cases the percentage R.F.C. was slightly higher in the stored than in the fresh blood mononuclear cells (overall mean % R.F.C. 61-8). In studies on human cord blood it has frequently been necessary to hold defibrinated samples overnight before separating the mononuclear leucocytes. The mean value and range for a % R.F.c. among those samples has not differed from the corresponding values for samples (from other individuals) processed within minutes of collection. In all cases rosettes have been counted after overnight incubation of the lymphocyte/erythrocyte mixture. A single specimen examined after seventy-two hours’ storage as whole blood gave a yield of only 20% R.F.C., indicating that in this case irreversible deterioration had occurred. We have found that mononuclear cells can be stored at room temperature in sterile culture medium with 20% fetal calf serum for at least forty-eight hours without change in the percentage of R.F.C. or of cells with surface Steel, C. M., Evans, J., Smith, M. A. Unpublished. Steel, C. M., Evans, J., Smith, M. A. Nature (in the press). Jondal, M., Holm, G., Wigzell, H. J. exp. Med. 1972, 136, 207. Wybran, J., Chantler, S., Fudenberg, H. H. Lancet, 1973, i, 126. Dwyer, J. M., Bullock, W. E., Fields, J. P. New Engl. J. Med. 1973, 288, 1036. 6. Urbaniak, S. J., Penhale, W. J., Irvine, W. J. Clin. exp. Immun. 1973, 15, 345. 7. Brain, P., Gordon, J., Willetts, W. A. ibid. 1970, 6, 681. 8. Lay, W. H., Mendes, N. F., Bianco, C., Nussenzweig, V. Nature, 1971, 230, 531. 9. Yata, J., Tsukimoto, I., Tachnibana, T. Clin. exp. Immun. 1973, 14, 319. 10. Harris, R., Ukaejiofo, E. O. Lancet, 1969, ii, 327. 1. 2. 3. 4. 5.
CYRIL A. CLARKE, Chairman, Executive Committee.
detects
polysaccharide produced by pathogenic pneumopolysaccharide derived from pharyngeal
cocci and not commensals.
known to have received prior antibiotic was detected in all 5 purulent sputa obtained from these 6 patients, in 5 urine samples, and in 3 sera; antigen was also detected in the pleural fluid of 4 of 6 patients who developed sterile pleural effusions whilst receiving antibiotics. C.LE. thus provides a rapid method for establishing an aetiological diagnosis in most patients with pneumococcal pneumonia and is little affected by prior antibiotic 6
patients
treatment.
were
Antigen
treatment.
BACTERIOLOGICAL FINDINGS IN PNEUMONIA
SIR,—Dr Spencer and Dr Philpand Dr Kinnell2 have raised some important points in regard to the bacteriological diagnosis of primary pneumonia. Dr Kinnell stresses the importance of accurate bacteriological diagnosis in view of the fact that penicillin-resistant organisms such as Staphylococcus aureus can produce classical lobar pneumonia. Sputum culture is, however, often unrewarding. Dr Kinnell isolated a potential pathogen from only 24% of sputa examined; Dr Spencer and Dr Philp isolated pathogens from a much higher proportion of untreated patients but obtained pathogens in only 31 % of the 52 of their 76 patients who had received some treatment before sputum culture. We are particularly interested in these observations since lobar pneumonia is the commonest cause of medical admission to the adult medical wards at Ahmadu Bello University Hospital, Zaria. We feel that sputum culture is of little value in the investigation of suspected pneumococcal pneumonia, as commensal pharyngeal pneumococci have been isolated from the upper respiratory tract in up to 60% of normal people,3and it has been reported4 that Streptococcus pneumonia failed to grow in over 40% of sputum samples in which numerous gram-positive diplococci were seen on direct smear. Str. pneumonia is isolated from the blood in only about a third of patients with pneumococcal pneumonia even when guineapig inoculation is carried out.5 Bacterial polysaccharide antigens can readily be demonstrated in biological fluids by counterimmunoelectrophoresis (c. I.E.); and pneumococcal antigen has been detected in the blood of patients with pneumococcal pneumonia, using C.LE.6,7 We have therefore carried out a prospective study of the value of C.LE. in establishing a bacteriological diagnosis in pneumonia (unpublished). 98 patients with radiologically proven lobar pneumonia were studied. C.LE. was carried out with pneumococcal antisera obtained from the Statens Seruminstitut, Copenhagen. Pneumococcal antigen was detected in 42 (79%) of 53 purulent sputa, in 42 (54%) of 78 urine samples, in 26 (27%) of 98 initial serum samples, and in 10 (83%) of 12 pleural effusions. In contrast, pneumococcal antigen was detected in only 3 of 40 purulent sputa from patients with pulmonary tuberculosis and in none of their serum or urine samples. The serotype of the pneumococcal polysaccharide present in sputum was identical with that found in the blood or urine in all but 1 of the 29 patients with lobar pneumonia investigated; this suggests that c.i.E. of the sputum only 1. 2. 3. 4. 5. 6. 7.
Spencer, R. C., Philp, J. R. Lancet, 1973, ii. 349. Kinnell, H. G. ibid. p. 919. Laurenzi, G. A., Potter, R. T., Kass, E. H. New Engl. J. Med. 1961, 265, 1273. Fiala, M. Am. J. med. Sci. 1969, 257, 44. Mufson, M. A., Chang, V., Gill, V., Wood, S. C., Romansky, M. J. Am. J. Epidem. 1967, 86, 526. Dorff, G. J., Coonrod, J. D., Rytel, M. W. Lancet, 1971, i, 278. Kenny, G. E., Wentworth, B. B., Beasley, R. P., Foy, H. M. Infect. Immun. 1972, 6, 431.
Department of Medicine, Ahmadu Bello University Hospital, Zaria, Northern Nigeria.
PETER TUGWELL BRIAN M. GREENWOOD.
FIBRE AND OBESITY
SIR,-Those of us who spent our professional lives in tropical Africa would like to express agreement with the suggestion of Dr K. W. Heaton (Dec. 22, p. 1418) that food fibre has an important role in preventing obesity. Personal observation can report that obesity was very rare in all East Africans in 1929 but became very common and often severe in upper socio-economic groups in 1950-70. In 1929 Africans ate a large amount of unprocessed carbohydrate foods, maize meal, millet meal, potatoes, plantains, and beans. No white wheat flour or white rice were eaten, and very little, if any, sugar, for local production had only just started. Apart from a few pastoral tribes, little milk and no butter were taken and no vegetable oil outside the coastal strip; margarine was unknown among them. Unprocessed groundnuts were almost the only source of vegetable fat, which like carbohydrate is formed with the plant cell wall of fibre. Africans took very little animal fat, for the wild animals and their domesticated goats, cattle, and sheep had little obesity or fat in their carcasses.
Many envisage plant fibre as a minute portion of our vegetable foods, for white flour contains crude fibre 0-1%. The unavailable carbohydrate and lignin, or dietary fibre, Wheat wholemeal as some are calling it,! is far larger. contains 10% of dietary fibre, celluloses 4%, hemicelluloses 6%.2 Fibre is an important constituent of the normal But neither the word fibre nor unavailable carboreceives much discussion in any book on obesity. Diabetes is a disease of carbohydrate metabolism and carbohydrate is formed within a vegetable cell wall of fibre, but the word fibre does not occur in the index of any journal specially devoted to the study of diabetes, and this disease was rare in East Africans in the 1930s.4
diet.3
hydrate
Woodgreen, Fordingbridge,
HUGH TROWELL.
Hants.
HEALTH CARE IN SOUTH AFRICA
SIR,-This is in reply to a comment by Dr Goodall (Dec. 22, p. 1436) on the thoroughly investigated and incisive paper somewhat critical of the health-care delivery to Blacks and Asians in South Africa. This paper has been labelled as political " by the commentator, after citing many achievements of South African equalisation of the quality of medical care, such as availability of all medicines to all people and an infant-mortality rate " appreciably less " disastrous than the worst in the world. I feel that considering the grossly discriminatory distribution "
1. 2. 3. 4.
Southgate, D. A. T. Plant Foods for Man, 1973, 1, 45. Fraser, J. R. J. Sci. Fd Agric. 1958, 9, 125. Cummings, J. H. Gut, 1973, 14, 69. Trowell, H. Non-infective Disease in Africa; p. 306. London, 1960.
96 of medical care and its quality in South Africa the situation there requires not only medical exposing but it is also in need of intensive political work and one can but congratulate The Lancet for the courage to enter a medicopolitical scene, so gravely neglected by the medical profession. To abrogate this political stance in favour of " pure science ", precluding any bias and political opinion, is in my opinion neglecting an important duty of all physicians. Attention to the distribution of health care and its quality, affecting all people, has been neglected by the medical profession in a rather self-seeking way. Medicine, dealing with people, is intrinsically political and we should recognise that, whether we want it or not, we will have to enter that arena. 55 East
Washington Street, Suite 2801,
ERIC C. KAST.
Chicago 3, Illinois.
MEDICAL/INDUSTRIAL
COMPLEX
SIR,-A correspondent writing in your " Round the World" column (Dec. 15, p. 1380) describes the U.S. medical/industrial complex " and refers to a series of articles in the New Yorker. His general description of the problem is fairly accurate and there is little doubt that in the field of occupational health the U.S. has lagged far behind Europe. That much of this is a consequence of pernicious behind-the-scenes lobbying, and of suitably large contributions to the election campaign funds of certain politicians, is beyond doubt. But as one who has been in occupational medicine for several years, and who can also claim to belong to the one organisation-namely, the National Institute of Occupational Safety and Health"
of Brodeur’s New Yorker diatribe with I feel that Brodeur grossly overstates much of his case. His description of the asbestos exposure incident in Texas is unfortunately only too true, but he then went on to "question the motives of all those who recommended a 5 fibre " asbestos standard. In doing so he implied that some of the most respected names in American and Canadian medicine, men with international reputations, were influenced by the fact that they were retained as consultants by industry. Many of those on whom such aspersions were cast are academicians, and as such precluded from receiving any It might be financial remuneration for their services. difficult for Brodeur to accept, but some companies are concerned about their employees and are willing to seek expert advice to see whether an industrial hazard exists. There are those who might be pardoned for thinking that Brodeur relied too much on the accuracy of the material that was given to him by some of the " heroes " of the New Yorker articles. In this regard, both labour and management have in the past contracted with certain groups (and doubtless will do so again) when they have been faced with occupational health problems. Unfortunately, too often the choice of contractor has been predicated on the contractor’s political sympathies rather than on his medical and scientific competence or on his objectivity. Let it be recognised that both management and labour have axes to grind, as witnessed by the recent support given by the combined labour/management asbestos lobby to those studies purporting to show that fibreglass is as dangerous as asbestos. Meanwhile, the one disinterested and impartial group, the National Institute of Occupational Safety and Health, is unable to assume all of its responsibilities owing to lack of staff.
that came colours still
out
flying, albeit a little tattered,
Department of Medicine, West Virginia University, Medical Center, West
Morgantown, Virginia 26506,
U.S.A.
W. K. C. MORGAN.
ROSETTING TESTS SIR,—MISS ilrvine and Dr cooper (.uec. , p. i440) report that identification of B and T cells among human peripheral blood lymphocytes may be unreliable if the samples have been stored for even a few hours before examination. Experience in this laboratory suggests that with appropriate techniques the effects of storage can be minimised. The proportion of peripheral blood mononuclear cells forming spontaneous rosettes with sheep erythrocytes (presumptive T cells) is, in our hands, 52-75% (mean 62%) in samples from healthy adults under conditions of normal daily activity. 1,2 These figures agree well with those recorded in a number of centres 3-8 but contrast with a mean value of less than 30% obtained by Irvine and Cooper and by some other groups.7-9 Among variable factors in the technique which may account for the discrepancy, the most critical appears to be some individual property of the sheep from which erythrocytes have been obtained.1 The period of incubation of the lymphocyte/erythrocyte mixture before counting rosettes is, however, also important, reproducibility of the counts increasing with prolonged incubation. One reason for this may be that deleterious effects of storage of the blood sample are slowly reversed when the lymphocytes are suspended in culture medium, as the following experiment suggests. Defibrinated blood samples from four healthy adults were each divided into two aliquots, one of which was processed immediately and the other held for two hours at room temperature before proceeding. Mononuclear cells separated from the samples by centrifugation over a ’Ficoll/Triosil ’ layer 10 were washed, resuspended in Ham’s‘ F10 ’ medium with 20% fetal calf serum, mixed with erythrocytes from a selected sheep, and spun down at 50 g for five minutes. Rosettes were counted (in triplicate samples) after one hour’s incubation of the lymphocyte/ erythrocyte mixtures at room temperature. In every case the stored blood had a lower percentage of rosette-forming cells (R.F.C.) than the corresponding fresh sample (mean values 58-1% and 63-2%, respectively). When counts were made on additional (triplicate) mixtures which had incubated overnight at room temperature the difference had disappeared and in two cases the percentage R.F.C. was slightly higher in the stored than in the fresh blood mononuclear cells (overall mean % R.F.C. 61-8). In studies on human cord blood it has frequently been necessary to hold defibrinated samples overnight before separating the mononuclear leucocytes. The mean value and range for a % R.F.c. among those samples has not differed from the corresponding values for samples (from other individuals) processed within minutes of collection. In all cases rosettes have been counted after overnight incubation of the lymphocyte/erythrocyte mixture. A single specimen examined after seventy-two hours’ storage as whole blood gave a yield of only 20% R.F.C., indicating that in this case irreversible deterioration had occurred. We have found that mononuclear cells can be stored at room temperature in sterile culture medium with 20% fetal calf serum for at least forty-eight hours without change in the percentage of R.F.C. or of cells with surface Steel, C. M., Evans, J., Smith, M. A. Unpublished. Steel, C. M., Evans, J., Smith, M. A. Nature (in the press). Jondal, M., Holm, G., Wigzell, H. J. exp. Med. 1972, 136, 207. Wybran, J., Chantler, S., Fudenberg, H. H. Lancet, 1973, i, 126. Dwyer, J. M., Bullock, W. E., Fields, J. P. New Engl. J. Med. 1973, 288, 1036. 6. Urbaniak, S. J., Penhale, W. J., Irvine, W. J. Clin. exp. Immun. 1973, 15, 345. 7. Brain, P., Gordon, J., Willetts, W. A. ibid. 1970, 6, 681. 8. Lay, W. H., Mendes, N. F., Bianco, C., Nussenzweig, V. Nature, 1971, 230, 531. 9. Yata, J., Tsukimoto, I., Tachnibana, T. Clin. exp. Immun. 1973, 14, 319. 10. Harris, R., Ukaejiofo, E. O. Lancet, 1969, ii, 327. 1. 2. 3. 4. 5.