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PULMONARY ARTERIAL PRESSURE
1016
electricity, thus saving much in labour, and that it effects an economy in manures, sterilising and so on. Just as much or more knowledge of how to grow plants at all is however needed to grow them without soil as with it. The system undoubtedly has a future, but more experimentation is wanted before it becomes a fully-fledged
partner of the age-old methods. In the
mean-
time the more trials that can be carried out by amateurs and professionals the better. There is not the slightest reason to suppose that the crops grown in this way will differ
in nutritional value from those grown in soil. The chemical substances on which thee food value of a vegetable or fruit depends are manufactured by the plant in the course of its growth and are not absorbed as such by the root; all that soilless cultivation can do is to ensure that the plants shall not be deficient in any of the elements for growth, such as nitrogen, potassium, phosphorus, calcium and the rest. But the mysterious qualities ascribed to these crops are mere moonshine invented by hopeful sellers of apparatus and chemicals.
ANNOTATIONS SERUM
IN CEREBROSPINAL FEVER
THE success of chemotherapy in meningococcal meningitis has quite suddenly relegated serum to a secondary place in treatment. Clearly chemotherapy must be employed whether serum is given or not but on another page Dr. Russell Amies pleads for a more extended trial of the combined treatment in human infections, a procedure which he regards as essentially rational. He shows that meningococcal septicaemia in mice can be treated more effectively by sulphapyridine plus serum than by either product alone, the case-fatality rate with the combined treatment being 26 per cent. as against 59 per cent. with sulphapyridine alone, 73 per cent. with serum alone, and 95 per cent. in untreated controls. It would be unjustifiable however to draw the obvious conclusion as far as human infections are concerned. Dr. Amies reminds us that the earliest use of chemotherapy in meningococcal meningitis was founded on mouse experiments but it must be said also that results far exceeded expectations. Moreover, although the accumulated data on combined treatment must by now be considerable, in no comparable series in the present epidemic has there been an improvement on the gross fatality-rate of 10 per cent. reported by Banks/ who used chemotherapy alone. As experience with the sulphonamide compounds crystallises emphasis is increasingly laid not only on the correct choice of preparation to meet varying circumstances but on precise dosage and early recognition of danger signals such as dehydration. Provided these details are mastered, chemotherapy alone appears to afford the patient the best chance of recovery we can offer at present. Nevertheless, serum will continue to be used, particularly in desperate cases of the fulminating type or when the patient is comatose when first seen, if for no other reason than an unwillingness to abandon a form of treatment which has proved helpful in the past. There must be no question however of reserving serum as a second line of defence to be used if the patient does not respond to chemotherapy. If any benefit is to be obtained from serum as an adjuvant it must be given immediately in a large dose (50-100 c.cm.) and preferably by the intravenous route. There is now general agreement that intrathecal administration does not offer any particular advantage but rather the reverse.
the lesser circulation. Many of these are mechanical, and it is good mental exercise to work out the nice coordination whereby two synchronised pumps, the left and right hearts, contrive without disaster to meet the capricious demands of the peripheral circulation. Disaster, as far as the lungs are concerned, would be a brief incoordination of sufficient magnitude to denude them of blood or congest them to the point of haemorrhage. Another point is the degree to which the pulmonary capillaries can constrict and* dilate actively, for a mass movement in either direction would profoundly influence the heart and the rest of the circulation. Experiments on animals tell us that such happenings normally fall far short of the calamitous, and that in the moment of cardiac adjustment to a new circulatory condition the pulmonary reservoir may perform an important function in buffering the differential output of the two sides of the heart. Clinical observation shows, nevertheless, how the failing left heart can become increasingly dependent on increased pressure in the left auricle which can only be transmitted from the right heart via the pulmonary capillaries. The stability of the lesser circulation can be attributed in great part to its large bed and low resistance, and the pulmonary arterial pressure is as a rule placed at about a sixth that of the systemic. Brock and Spurrellhave for the first time measured it directly in man, confirming this order of magnitude and showing that it diminishes on inspiration and increases on expiration. It is to be hoped that they may succeed, by more sensitive recording, in registering the pulse-pressure. It is perhaps too much to hope that the limits of variation, the effects of cardiac embarrassment, the influence of high coronary flow and so forth will ever be determined on the operatingtable. On the other hand it is impossible to predict what important result may not accrue from simple measurements of this kind made as opportunity serves
during surgical operations. THE DYSENTERY BACILLI
AFTER
mighty expenditure of labour Colonel Boyd4 has brought order out of the chaos of organisms which may cause bacillary dysentery. His results are based on the isolation of a very large number of organisms in the military laboratories of India. In order to obtain criteria of pathogenicity the stools of 93,000 menials in India, making between 8000 and 9000 platings, were examined, and pathoPULMONARY ARTERIAL PRESSURE genic dysentery bacilli were never isolated, except from THE chief function ol the pulmonary circulation men suffering from acute or chronic dysentery. This the lies in between undoubtedly gaseous exchange blood and alveolar air. In his Harveian oration out- observation was confirmed by others from some lining the historical growth of this conception, R. A. 119,000 platings. The pathogenic dysentery bacilli Youngdiscussed some other points associated with 3. Brock, R. C. and Spurrell, W. R. Guy’s Hosp. Rep. 1939, 89, a
262.
1. Banks, H. S. see Lancet, May 25, 1940, p. 966. 2. Lancet, Jan. 6, 1940, p. 1.
4.
Boyd, J. S. K. Trans. R. Soc. trop. Med. Hyg. April, 1940, p. 553.
electricity, thus saving much in labour, and that it effects an economy in manures, sterilising and so on. Just as much or more knowledge of how to grow plants at all is however needed to grow them without soil as with it. The system undoubtedly has a future, but more experimentation is wanted before it becomes a fully-fledged
partner of the age-old methods. In the
mean-
time the more trials that can be carried out by amateurs and professionals the better. There is not the slightest reason to suppose that the crops grown in this way will differ
in nutritional value from those grown in soil. The chemical substances on which thee food value of a vegetable or fruit depends are manufactured by the plant in the course of its growth and are not absorbed as such by the root; all that soilless cultivation can do is to ensure that the plants shall not be deficient in any of the elements for growth, such as nitrogen, potassium, phosphorus, calcium and the rest. But the mysterious qualities ascribed to these crops are mere moonshine invented by hopeful sellers of apparatus and chemicals.
ANNOTATIONS SERUM
IN CEREBROSPINAL FEVER
THE success of chemotherapy in meningococcal meningitis has quite suddenly relegated serum to a secondary place in treatment. Clearly chemotherapy must be employed whether serum is given or not but on another page Dr. Russell Amies pleads for a more extended trial of the combined treatment in human infections, a procedure which he regards as essentially rational. He shows that meningococcal septicaemia in mice can be treated more effectively by sulphapyridine plus serum than by either product alone, the case-fatality rate with the combined treatment being 26 per cent. as against 59 per cent. with sulphapyridine alone, 73 per cent. with serum alone, and 95 per cent. in untreated controls. It would be unjustifiable however to draw the obvious conclusion as far as human infections are concerned. Dr. Amies reminds us that the earliest use of chemotherapy in meningococcal meningitis was founded on mouse experiments but it must be said also that results far exceeded expectations. Moreover, although the accumulated data on combined treatment must by now be considerable, in no comparable series in the present epidemic has there been an improvement on the gross fatality-rate of 10 per cent. reported by Banks/ who used chemotherapy alone. As experience with the sulphonamide compounds crystallises emphasis is increasingly laid not only on the correct choice of preparation to meet varying circumstances but on precise dosage and early recognition of danger signals such as dehydration. Provided these details are mastered, chemotherapy alone appears to afford the patient the best chance of recovery we can offer at present. Nevertheless, serum will continue to be used, particularly in desperate cases of the fulminating type or when the patient is comatose when first seen, if for no other reason than an unwillingness to abandon a form of treatment which has proved helpful in the past. There must be no question however of reserving serum as a second line of defence to be used if the patient does not respond to chemotherapy. If any benefit is to be obtained from serum as an adjuvant it must be given immediately in a large dose (50-100 c.cm.) and preferably by the intravenous route. There is now general agreement that intrathecal administration does not offer any particular advantage but rather the reverse.
the lesser circulation. Many of these are mechanical, and it is good mental exercise to work out the nice coordination whereby two synchronised pumps, the left and right hearts, contrive without disaster to meet the capricious demands of the peripheral circulation. Disaster, as far as the lungs are concerned, would be a brief incoordination of sufficient magnitude to denude them of blood or congest them to the point of haemorrhage. Another point is the degree to which the pulmonary capillaries can constrict and* dilate actively, for a mass movement in either direction would profoundly influence the heart and the rest of the circulation. Experiments on animals tell us that such happenings normally fall far short of the calamitous, and that in the moment of cardiac adjustment to a new circulatory condition the pulmonary reservoir may perform an important function in buffering the differential output of the two sides of the heart. Clinical observation shows, nevertheless, how the failing left heart can become increasingly dependent on increased pressure in the left auricle which can only be transmitted from the right heart via the pulmonary capillaries. The stability of the lesser circulation can be attributed in great part to its large bed and low resistance, and the pulmonary arterial pressure is as a rule placed at about a sixth that of the systemic. Brock and Spurrellhave for the first time measured it directly in man, confirming this order of magnitude and showing that it diminishes on inspiration and increases on expiration. It is to be hoped that they may succeed, by more sensitive recording, in registering the pulse-pressure. It is perhaps too much to hope that the limits of variation, the effects of cardiac embarrassment, the influence of high coronary flow and so forth will ever be determined on the operatingtable. On the other hand it is impossible to predict what important result may not accrue from simple measurements of this kind made as opportunity serves
during surgical operations. THE DYSENTERY BACILLI
AFTER
mighty expenditure of labour Colonel Boyd4 has brought order out of the chaos of organisms which may cause bacillary dysentery. His results are based on the isolation of a very large number of organisms in the military laboratories of India. In order to obtain criteria of pathogenicity the stools of 93,000 menials in India, making between 8000 and 9000 platings, were examined, and pathoPULMONARY ARTERIAL PRESSURE genic dysentery bacilli were never isolated, except from THE chief function ol the pulmonary circulation men suffering from acute or chronic dysentery. This the lies in between undoubtedly gaseous exchange blood and alveolar air. In his Harveian oration out- observation was confirmed by others from some lining the historical growth of this conception, R. A. 119,000 platings. The pathogenic dysentery bacilli Youngdiscussed some other points associated with 3. Brock, R. C. and Spurrell, W. R. Guy’s Hosp. Rep. 1939, 89, a
262.
1. Banks, H. S. see Lancet, May 25, 1940, p. 966. 2. Lancet, Jan. 6, 1940, p. 1.
4.
Boyd, J. S. K. Trans. R. Soc. trop. Med. Hyg. April, 1940, p. 553.