cause of intrinsic difficulties. The possibilities of error in observation and of confusion of data are present in an unusual degree. The preceding discussion of this subject, which is based largely on the writer's personal observations, is intended to be only cursory and suggestive, and not conclusive or dogmatic, and the following statements, which are based on the preceding discussion, are offered for what they may be worth:

1. A low systolic pressure, provided the diastolic pressure is sufficiently low to provide an adequate pulse-pressure, does not necessarily mean poor circulation, though it does seem to imply a diminished reserve power of the heart.

2. A comparatively low systolic pressure with a comparatively high diastolic pressure and a consequently small pulse-pressure may mean myocardial weakness with chronic nephritis, arteriosclerosis, chronic toxæmia, or arterial spasm.

3. A low diastolic pressure with a comparatively high systolic pressure and an excessively large pulse-pressure may mean several things; e.g., a purely functional condition, a compensated aortic regurgitation, myocardial degeneration without much arteriosclerosis or chronic nephritis, or vasodilatation from any cause.

4. The diastolic pressure seems to be more stable than the systolic, and to show less often than the systolic marked variations from its normal without definite pathologic cause; and the systolic pressure seems to accommodate itself to the diastolic more easily than the diastolic to the systolic in conditions of disease. The diastolic pressure seems to indicate the peripheral resistance, which in many cases is determined by definite pathologic conditions. Movements of the diastolic pressure beyond the normal range seem to be a sufficient cause for enlargement of the pulse-pressure if an adequate circulation is to be kept up.

5. Heart stimulant drugs seem to improve the circulation in some cases, even when they do not raise the systolic pressure.

6. It is possible that vasodilator drugs may improve the circulation by increasing the pulse-pressure.

7. Cardiac depressant drugs may lower the diastolic pressure by diminishing the systolic force and thereby calling for an enlargement of the pulse-pressure.

8. A systolic pressure of 100 or lower in an adult, if persistent, may call for treatment.

9. A diastolic pressure of 100 or higher, if persistent, suggests disease.

10. It may be possible for a patient to live for several hours with a systolic pressure as low as 60, for several days with one of 70, and to walk around without particular symptoms of circulatory distress with one of 90, provided the pulse-pressure is sufficiently large.

11. A pulse-pressure as small as 20 or as large as 60, if persistent, may be pathologic.

12. A systolic pressure persistently over 140 in a young or middleaged adult suggests disease.

13. A fall in the systolic pressure in response to an exercise test, immediately or after a short preliminary rise, and a delay in its return to the normal, and also at the same time a failure of the pulse-pressure to show a substantial increase in size, suggest myocardial weakness.

14. Shortly before death partial asphyxiation may cause a sudden, transient rise in the blood-pressure.

15. Toxæmias, both acute and chronic, may lower the systolic pressure without much increase or with some diminution in the pulsepressure.

16. In some cases with high blood-pressure, lowering of the pressure follows the taking of a non-putrefactive diet, and the amount of the lowering seems inversely to correspond more or less with the degree of development of coexisting chronic nephritis or arteriosclerosis.

17. Chronic tobacco poisoning seems often to be attended with low blood-pressure.

18. Chronic nephritis seems regularly to be attended with a high diastolic pressure and a large pulse-pressure, which is adequate so long as the myocardial reserve power holds out.

19. Arteriosclerosis, as a rule, seems to produce marked elevation of the blood-pressure only when the blood supply of a vital region is disturbed or when the aorta is affected.

20. The neurotic factor in the patient and the personal factor in the observer may require a considerable allowance to be made for them in the interpretation of blood-pressure findings; and it is necessary to be constantly on guard against being misled by blood-pressure findings, and especially against ascribing too much importance to them when unsupported by other evidences of disease.

Surgery

A VISIT TO THE SURGICAL CLINIC OF JOHN B. MURPHY AT THE MERCY HOSPITAL IN CHICAGO

BY P. G. SKILLERN, Jr., M.D.

Philadelphia

It is the ambition of every surgeon in his study travels to visit the clinic of that great and peerless teacher, originator, and investigator, Dr. John B. Murphy. If the pilgrim has been inspired by reading Dr. Murphy's published " Clinics," it proves a source of much gratification to him to discover that Dr. Murphy talks just as he writes, and that all that appears in the volumes is demonstrated and discussed at the operating table.

The Mercy Hospital is a handsome brick building, situated at Twenty-sixth Street and Prairie Avenue, and of the most modern type. After a walk through a long corridor one descends the steps to the operating room, which may be reached more directly by the entrance at Twenty-sixth Street and Calumet Avenue. The reporter was gowned and directed to a stool in the pit of the theatre, whence a view of each operation was afforded at very close range.

The theatre accommodates five hundred spectators, the daily attendance averaging about one-third that number. A unique feature is that every day as many as thirty-five States in the Union are represented, as well as Canada and foreign countries. The seats face the large pit and the ample windows, which admit light from the north. The lower windows are of glazed glass, upon which are written the list of operations and statistical tables for the day. One hour previous to Dr. Murphy's arrival his assistants have been busy hanging up the charts, tables, etc., appropriate to the cases of the day. These charts are renewed as each case comes in.

Dr. Murphy's teaching methods are of great interest. He is a firm believer in the efficiency of ocular demonstrations. Not only are

there numerous charts, but he has also a large collection of bones, normal and pathologic, with which he illustrates his comments made during the course of bone operations. There are also within reach a large number of photographs and skiagrams. For example, when performing an arthroplasty of the knee-joint he relates case after case from his great experience, illustrating the various phases that come into question. Dr. Murphy talks in a clear-cut and forceful manner. First the history of the case is read by the interne, who is interrupted by interrogations when the anamnesis is not clear. Dr. Murphy then discusses the case, its pathology, and particularly the diagnosis, while preparations for operation are being made, continuing the discussion during the operation and upon its conclusion summing up all the points. The medical aspect of border-line cases is discussed by Dr. Mix.

Dr. Murphy enters the pit shortly after nine o'clock, and finishes the sterilization of his hands. He then puts on elbow-length fabric gauntlets, over which are drawn dry rubber gloves. The operating table is wheeled in bearing the patient, to whom ether is being administered by the Sister Ethelreda. A small mask is used and the ether dropped on from its original container, regulation of the flow being obtained by a gauze wick held in place by the cork stopper. A large tank of oxygen is wheeled in by the Sister's side, ready for use. A rubber cork tunnelled mouth-gag is used when necessary, holding the jaws apart and at the same time permitting the patient to breathe through it. The table is placed in the most advantageous position for the spectators. The skin is prepared with iodine, and a perforated sheet, bearing four towels secured around the opening, is laid upon the patient. Dr. Murphy begins the incision with his razor-scalpel, which makes a very clean wound, with surprisingly little hemorrhage. The operation proceeds deliberately and smoothly. A stenographer, seated on the front row, takes down Dr. Murphy's comments. Such details as swatting" the occasional flies are carried out by an attendant. Ample illumination is afforded by a cluster of Mazda lamps in a holophane shade, which is suspended from an arm of heavy brass tubing attached to the wall in such a manner that it may be pushed in and out and swung from side to side. In addition to this, Dr. Murphy wears an electric lamp suspended from his forehead by a metallic head-band.

There are three assistants: one responsible for the instruments,