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Ditto. 4 years.
Ditto. 6 months.
Ditto. Sickly 12 months. Ditto. 4 weeks.
Ditto. 18 months,
Ditto. 15 months.
Ditto. 8 months,
Ditto. 4 months.
Ditto. 4 months.
Carpenter. 1 month.
Ditto. 2 years.
Ditto. 1 year.
Ditto. 2 years.
8 months. Palpitation 1 week.
3 months. 3 years. 3 months.
From this table, we learn certain laws relating to the occurrence of subclavian murmur in diseased states, which are of considerable interest. A few illustrations may be given.
In the first place, there is no case of a child presenting the murmur. The youngest subjects named were eighteen years old. There were, nevertheless, many children included in the total of cases, the majority of whom were suffering from the diseases named in the table. In the case of every child, I examined with more than ordinary care for the mur
I often found the common anæmic continuous murmur in the neck, but never the subclavian.
Next, we see that the subclavian murmur is rare in females. In the total of cases (2000) from which the deductions were drawn, there were more females than males in the proportion of about one per cent. ; yet there were 3 cases only of the murmur on the female side to 48 on the male side. The murmur in the female, moreover, when it did occur, was not to be heard without an effort on the part of the patient to bring it out, such as a long inspiration: it was also much more faint, and even more fleeting, in the women than in the men.
Thirdly, we see from the table, that the murmur as occurring in disease is most peculiar in certain forms of disease. Chronic bronchial affections are those which furnish most illustrations of it, according to my analysis, viz., 18 to the 2000; afterwards stands phthisis, yielding 12 cases; next anæmia, giving 10 cases ; next dyspepsia, yielding 7 cases; then heart-disease,
giving 3 cases; and, lastly, a single case of bronchial affection combined with tubercular deposit. These relationships will have to be further considered in
Finally, the table shows a curious circumstance in reference to occupation. It will be seen that, in the vast majority of the cases, the patients were employed in manual labours, in the exercise of which the arms are thrown forwards and downwards. Thus there are no fewer than fifteen cabinet-makers in the list; men who are engaged all their lives in planing, sawing, and polishing. There are four carpenters, two sawyers; and so on. When I first observed this connection of the murmur with certain mechanical arts, I began to inquire into the matter carefully. I thought it might be that the men of these trades were more fully represented in the list of patients than others. This turned out to be a fallacy; for, of the 2000, there were many more tailors than cabinetworkers, and more clerks than tailors, and more sempstresses than clerks. I began consequently to inquire how far the special occupation influenced the result. To get at the truth in this direction, I collected eight cabinet-makers who were quite well, and to my surprise found that they all presented the murmur. I extended the observation to carpenters also, and found the same thing, though not so frequently. Blending, therefore, these facts with those which tell us how rare the murmur is in women, and that it is absent in children, I am driven to the inference that particular mechanical actions of the arms long continued, have an influence in producing the peculiar sound; how and why, we shall see better in a succeeding page.
CAUSE AND CAUSATION OF SUBCLAVIAN MURMUR.
The whole tenor of my observations leads me to the conviction that subclavian murmur is of arterial origin. In this view I shall be supported by the majority of auscultators, but shall be at variance with at least one, I mean Dr. Thorburn, who, speaking of the sound, remarks: “It must either be a respiratory sound modified by the heart and great blood vessels, so as to have a cardiac rhythm; or a vascular sound modified by respiration. From a careful examination, I have come to the conclusion that it is of the former character: and that what is heard is the expiratory murmur and the end of the inspiratory murmur itself, saccadée or jerked by some undue impulse. I think it probable that this impulse is communicated by a nervously excited or perhaps slightly dilated aorta, just as the action of the heart may sometimes give a cardiac rhythm to a friction-sound which is really pleural. The greater comparative weakness of expiration will account for its being heard chiefly at that time.”
I have said that Dr. Thorburn is alone in his opinion; but his hypothesis is ingenious, and well put. It is necessary, therefore, in disposing of it, to use careful and logical argument in favour of the opposite view; viz., that subclavian murmur is an arterial sound, modified by respiration. The proofs of