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PAIN IN PECTORALIS MINOR
785
point was raised which may have a considerable bearing on hospital finances. It was stated that the majority of errors of radiography are due to inadequate use of the method. Although it is well known that many One
lesions can be hidden in the mediastinum, a lateral view which will reveal such lesions is not carried out as a routine. It was also shown that the combination of postero-anterior and antero-posterior views will uncover small areas of disease concealed by the ribs and breasts, and it was suggested that an adequate initial examination should comprise three views. Such a procedure would greatly increase costs, but it was argued that the cost of chronic pulmonary disease is so colossal that any method ,leading to its earlier detection would warrant the
expenditure. The comparative value of radiology and the stethoscope in cardiology was not discussed in detail, and it was admitted that radiology lagged far behind. Fluoroscopy now plays an essential part in the examination of the heart, but it was suggested that future developments in radiography would result in an increasing use of the X-ray machine at the expense of the stethoscope. NATURAL HISTORY OF VIRUSES TfiosE who were at Harvard University last year to hear Dr. F. M. Burnet, FRS, of Melbourne, deliver his Edward K. Dunham lectures on the natural history of virus diseases must have found it a stimulating experience, and it is fortunate that the lectures have now been expanded and printed as a monograph.! The theme running through the monograph is that the infectious diseases of man can be correctly understood only if the subject is approached as an ecological problem concerning the interaction of two species. Dr. Burnet is a convinced exponent of the view that viruses are micro-organisms, and he accepts the conception, originally and independently propounded by Laidlaw in Britain and by Green in America, that viruses have arisen from higher forms of microbial life by a degenerative adaptation to an intracellular parasitic existence. (Strangely enough his bibliography does not include any of the papers by Green and Laidlaw’ on this subject.) Dr. Burnet is in no way dismayed at having to fit the very, small viruses or even the plant viruses into this theory. As he points out, future work will probably show that protein production, a strictly biological activity, is a process of replication by subcellular, but essentially living, entities,and if this is so the dispute as to whether the very small viruses are protein molecules or micro-organisms Burnet thinks that all virus reprobecomes unreal. duction takes place in this way, though it remains to be discovered how the virus draws the material and energy from the host cell for this replication ; there is an indication from the interference phenomenon that one essential is some pseudo-immunological union between the virus particles and cell constituents. When he discusses some representative virus diseases in turn Dr. Burnet starts with herpes, since its story is relatively simple. Infection with this virus occurs in infancy or early childhood and persists throughout life, only revealing itself when, from time to time, the balance between host and parasite is upset ; very rarely does this infection prove fatal. Dr. Burnet considers, therefore, that herpes is an excellent example of the way in which an infectious disease can reach a state of equilibrium in which the chances for dissemination of infection are maximal but the effects of the infection The natural history of polioon the host are minimal. myelitis is much less clear, largely because of the lack of a cheap susceptible animal. For this reason Dr. Burnet thinks that advances will come from. a study of mouse paralysis, a naturally occurring disease shown by Theiler to be due to a virus closely allied to poliomyelitis. Psittacosis is of particular interest in tracing the evolu1. Virus as Organism.
Oxford University Press.
Pp. 134. 11s. 6d.
tion of
viruses, since, with other related viruses, it forms
connecting link between the rickettsias on one hand and the more typical viruses on the other. There is evidence, moreover, that examples of man-to-man transfer of psittacosis are not uncommon, and that, if such a mode of transfer becomes established, connexion with the avian disease might be lost and a specifically human infection might arise. a
PAIN IN PECTORALIS MINOR TiiE established case of angina pectoris is easily recognised, but the differential diagnosis in the early stages is becoming increasingly complicated. The latest condition to be described as simulating angina pectoris is strain of the pectoralis minor muscle, which, in the opinion of an American observer, ranks second to psychoneurosis and the anxiety state as a cause of precordial pain in men of military age. In such cases there may be no history of trauma, and the presenting symptom is pain, usually in the midclavicular region of the chest at the level of the 3rd, 4th, and 5th ribs, sometimes radiating to the shoulder but never down the arm. The pain may be intermittent, and it may appear to be related to exertion, but careful investigation shows that this is only so if the effort involves movement of the upper limb. The pain can be reproduced by making the patient push the upper arm forward against resistance when the elbow is at the side and behind the axis of the body. There is tenderness over the pectoralis minor, maximal at the site of the pain, and injection of procaine at this site abolishes the pain. Heat, massage, and local rest usually bring relief within a few days, but in two cases the attacks of pain recurred over a period of years. It is suggested that the pain is due to rupture of the pectoralis minor at its insertion into the chest wall. This is by no means the first time that attention has been drawn to the rupture of muscle fibres or fibrositis in the differential diagnosis of angina pectoris, but it seems to be the first time that this particular lesion has been incriminated. Two facts should always be remembered in examining suspected cases of angina pectoris : that a full and careful history is essential for correct diagnosis, and that the pain of angina is substernal.
CAMBRIDGE INSTRUMENT-MAKERS
IN 1883 when Michael Foster was appointed to the chair of physiology in Cambridge almost all scientific apparatus was imported from abroad. Foster needed a workshop and a skilled instrument-maker to equip his laboratory and he was fortunate in finding Dew-Smith to answer that need. From this modest back room with its treadle lathe and vice the Cambridge Scientific Instrument Company2 was developed. Horace Darwin, son of Charles Darwin, was one of the first partners and designers, and among his early work were anthropological instruments for Francis Galton, cloud cameras for Kew Observatory, and tools for the physical laboratories of the university. Perhaps the best known of Darwin’s inventions was the rocking microtome which was capable of cutting microscopical sections as thin as 00001 inch. The " rocker," almost in its original form, is still used in many laboratories throughout the world. Towards the end of the nineteenth century new universities were built in the Dominions and in America, and Cambridge instruments found a place in many of them. At this time also there was a growing demand for precision instruments in industry, and under the direction of such men as Callendar and Whipple many temperaturemeasuring devices were introduced. The investigations of Starling and James Mackenzie into the mode of action of the heart demanded accurate recording instruments,
new
1. Mendlowitz, M. Amer. Heart J. 1945, 30, 123. 2. Fifty Years of Scientific Instrument Manufacture. Report from Engineering, May 11 and 25, June 15 and 29, 1945.
point was raised which may have a considerable bearing on hospital finances. It was stated that the majority of errors of radiography are due to inadequate use of the method. Although it is well known that many One
lesions can be hidden in the mediastinum, a lateral view which will reveal such lesions is not carried out as a routine. It was also shown that the combination of postero-anterior and antero-posterior views will uncover small areas of disease concealed by the ribs and breasts, and it was suggested that an adequate initial examination should comprise three views. Such a procedure would greatly increase costs, but it was argued that the cost of chronic pulmonary disease is so colossal that any method ,leading to its earlier detection would warrant the
expenditure. The comparative value of radiology and the stethoscope in cardiology was not discussed in detail, and it was admitted that radiology lagged far behind. Fluoroscopy now plays an essential part in the examination of the heart, but it was suggested that future developments in radiography would result in an increasing use of the X-ray machine at the expense of the stethoscope. NATURAL HISTORY OF VIRUSES TfiosE who were at Harvard University last year to hear Dr. F. M. Burnet, FRS, of Melbourne, deliver his Edward K. Dunham lectures on the natural history of virus diseases must have found it a stimulating experience, and it is fortunate that the lectures have now been expanded and printed as a monograph.! The theme running through the monograph is that the infectious diseases of man can be correctly understood only if the subject is approached as an ecological problem concerning the interaction of two species. Dr. Burnet is a convinced exponent of the view that viruses are micro-organisms, and he accepts the conception, originally and independently propounded by Laidlaw in Britain and by Green in America, that viruses have arisen from higher forms of microbial life by a degenerative adaptation to an intracellular parasitic existence. (Strangely enough his bibliography does not include any of the papers by Green and Laidlaw’ on this subject.) Dr. Burnet is in no way dismayed at having to fit the very, small viruses or even the plant viruses into this theory. As he points out, future work will probably show that protein production, a strictly biological activity, is a process of replication by subcellular, but essentially living, entities,and if this is so the dispute as to whether the very small viruses are protein molecules or micro-organisms Burnet thinks that all virus reprobecomes unreal. duction takes place in this way, though it remains to be discovered how the virus draws the material and energy from the host cell for this replication ; there is an indication from the interference phenomenon that one essential is some pseudo-immunological union between the virus particles and cell constituents. When he discusses some representative virus diseases in turn Dr. Burnet starts with herpes, since its story is relatively simple. Infection with this virus occurs in infancy or early childhood and persists throughout life, only revealing itself when, from time to time, the balance between host and parasite is upset ; very rarely does this infection prove fatal. Dr. Burnet considers, therefore, that herpes is an excellent example of the way in which an infectious disease can reach a state of equilibrium in which the chances for dissemination of infection are maximal but the effects of the infection The natural history of polioon the host are minimal. myelitis is much less clear, largely because of the lack of a cheap susceptible animal. For this reason Dr. Burnet thinks that advances will come from. a study of mouse paralysis, a naturally occurring disease shown by Theiler to be due to a virus closely allied to poliomyelitis. Psittacosis is of particular interest in tracing the evolu1. Virus as Organism.
Oxford University Press.
Pp. 134. 11s. 6d.
tion of
viruses, since, with other related viruses, it forms
connecting link between the rickettsias on one hand and the more typical viruses on the other. There is evidence, moreover, that examples of man-to-man transfer of psittacosis are not uncommon, and that, if such a mode of transfer becomes established, connexion with the avian disease might be lost and a specifically human infection might arise. a
PAIN IN PECTORALIS MINOR TiiE established case of angina pectoris is easily recognised, but the differential diagnosis in the early stages is becoming increasingly complicated. The latest condition to be described as simulating angina pectoris is strain of the pectoralis minor muscle, which, in the opinion of an American observer, ranks second to psychoneurosis and the anxiety state as a cause of precordial pain in men of military age. In such cases there may be no history of trauma, and the presenting symptom is pain, usually in the midclavicular region of the chest at the level of the 3rd, 4th, and 5th ribs, sometimes radiating to the shoulder but never down the arm. The pain may be intermittent, and it may appear to be related to exertion, but careful investigation shows that this is only so if the effort involves movement of the upper limb. The pain can be reproduced by making the patient push the upper arm forward against resistance when the elbow is at the side and behind the axis of the body. There is tenderness over the pectoralis minor, maximal at the site of the pain, and injection of procaine at this site abolishes the pain. Heat, massage, and local rest usually bring relief within a few days, but in two cases the attacks of pain recurred over a period of years. It is suggested that the pain is due to rupture of the pectoralis minor at its insertion into the chest wall. This is by no means the first time that attention has been drawn to the rupture of muscle fibres or fibrositis in the differential diagnosis of angina pectoris, but it seems to be the first time that this particular lesion has been incriminated. Two facts should always be remembered in examining suspected cases of angina pectoris : that a full and careful history is essential for correct diagnosis, and that the pain of angina is substernal.
CAMBRIDGE INSTRUMENT-MAKERS
IN 1883 when Michael Foster was appointed to the chair of physiology in Cambridge almost all scientific apparatus was imported from abroad. Foster needed a workshop and a skilled instrument-maker to equip his laboratory and he was fortunate in finding Dew-Smith to answer that need. From this modest back room with its treadle lathe and vice the Cambridge Scientific Instrument Company2 was developed. Horace Darwin, son of Charles Darwin, was one of the first partners and designers, and among his early work were anthropological instruments for Francis Galton, cloud cameras for Kew Observatory, and tools for the physical laboratories of the university. Perhaps the best known of Darwin’s inventions was the rocking microtome which was capable of cutting microscopical sections as thin as 00001 inch. The " rocker," almost in its original form, is still used in many laboratories throughout the world. Towards the end of the nineteenth century new universities were built in the Dominions and in America, and Cambridge instruments found a place in many of them. At this time also there was a growing demand for precision instruments in industry, and under the direction of such men as Callendar and Whipple many temperaturemeasuring devices were introduced. The investigations of Starling and James Mackenzie into the mode of action of the heart demanded accurate recording instruments,
new
1. Mendlowitz, M. Amer. Heart J. 1945, 30, 123. 2. Fifty Years of Scientific Instrument Manufacture. Report from Engineering, May 11 and 25, June 15 and 29, 1945.