cases, or when its testimony may for some reasons that may occur, prove of service.

The amount of time employed in the act of inspiration, I may mention, is well denoted by this instrument. The short time of inspiration and the prolonged period of expiration in phthisis are made very manifest by the rapid ascent and the slow fall of the liquid in the tube.

This same instrument possesses some value to the scientific physician, in making obvious to the eye the movements of the heart, when that organ is displaced, as is so often the case in phthisis, in the third and fourth stages. When the heart is near the surface, it can generally be felt and seen at the second interspace on one or other side; but when it is still covered by some pulmonary structure, or when the cavity is small, the application of the sphygmoscope, for it is now a sphygmoscope (sphygmos, pulsus cordis), will render the obscure impulse more manifest. The liquid is more sensible, so to speak, to the motion of the heart than the eyes of the observer. In other words, the liquid set in motion in the tube is more obvious to the eye, than the motion of the chest caused by the underlying heart. The mamma is not sufficiently indicated in the cut.

10

Pneumatoscope.

When the heart's impulse is to be tested by the application of the sphygmoscope, a modification of the instrument may be employed, though its manifestations are less delicate. The stand may be dispensed with, and a glass cup and tube

alone employed. A piece of flexible tubing may be interpo sed between the cup and the glass tube: this admits of more free movement of the instrument, and is calculated to reduce the chance of breakage. See engraving representing sphygmoscopes, fig. 3:

Fig. 1. Artery sphygmoscope. Bore of tube 1-16th of an inch.

Fig. 2. Portable heart sphygmoscope. A, Glass cup, containing coloured water. B, Lamina of india-rubber, covering the mouth of the cup. C, Glass tube; bore 1-10th of an inch. D, Graduated scale. E, Screw-stopper.

Fig. 3. Heart sphygmoscope supplied with india-rubber tube, to admit of greater facility of comparison with movement of artery sphygmoscope, and greater readiness of observation when listening to the sounds of the heart.

Fig. 4. Artery sphygmoscope, with india-rubber tube.

The determination of the time of murmurs of the heart in phthisis is aided by this instrument. If we listen with the differential or double stethoscope for the sound, and look at the same time at the sphygmoscope, we can at once tell whether the murmur be systolic or diastolic. Every murmur heard during the ascent of the liquid is systolic, and every

murmur heard during the descent is diastolic. I may mention the fact, though perhaps a little out of place, that if the differential stethoscope gives heard sound or makes it appreciable, at the base, the murmur is basic; and if at the apex, the murmur is apicial.

As these instruments are comparatively little known to the medical world, I have ventured to add to this work my papers upon them, published by the Royal Society and "The Medical Times," and a plate taken from the "Archives of Medicine." It is remarkable that this very morning (Nov. 2, 1860) I have received from my kind friend Dr. C. B. Williams, a copy of the work of M. Groux, on the subject of Fissura Sterni, and that I find in it a drawing of my sphygmoscopes. It also contains an extract from a paper by Dr. J. B. Upham, of Boston, United States, read before the Boston Society for Medical Improvement, and published in the "Boston Medical and Surgical Journal." As the extract contains perhaps more trustworthy testimony than any that I could myself bear to the merits of these instruments, I would here insert it. "The delicate and beautiful instrument of Dr. Scott Alison, of London, called the sphygmoscope, has added much to the facilities of determining this vexed point"--the synchronism or non-synchronism of the various motions of the heart and great vessels as displayed by M. Groux. On perusing the work of M. Groux, I am greatly struck to find that the sphygmoscope has been converted into an acoustic appliance, and is made to act even upon the ear. This remarkable result has been achieved, to his great honour, by Dr. Upham, by the application of an electro-magnetic machine with a bell attached to it. As the liquid in the sphygmoscope rises, it breaks contact in the electro-magnetic machine, and a hammer falling upon a bell a sound is instantly obtained. The successive movements of sphygmoscopes applied to different parts of the heart and the arterial tree are signalised by successive sounds. To the courtesy of Dr. Williams I am indebted for an opportunity of witnessing and hearing these very remarkable and novel results. On the 2nd Nov., 1860, I witnessed the operation of the sphygmosphone of Dr. Upham upon the heart of M. Groux, at Dr. Williams' house, when Dr. Quain was also present.

The surprising and brilliant feat has been accomplished with the aid of the sphygmoscope and an electro-magnetic instrument, to record through the medium of the wires of an electric telegraph, the movements of the heart, at a distance of three miles and a half. This experiment, performed by

M. GROUX AND DR. UPHAM'S SPHYGMOSPHONE.

347

Dr. Upham upon M. Groux, was accomplished successfully in the United States of America last year. While M. Groux sat in Boston the movements of his heart were recorded at Cambridge.

A pneumatoscope has long been employed to ascertain the pressure of the expired air. The construction and principle of this instrument are altogether different from those of the instruments I have been describing.

TO MEASURE DIAMETERS. - Dr. Stokes and other physicians have recommended the employment of callipers for the purpose of taking diameters of the chest. In treating of the shape of the chest in phthisis, notice has been taken of depression of the anterior and upper part of the chest. To measure the amount of depression and the reduction of the cavity of the thorax, none of the instruments already noted are well adapted. There may be much depression, and yet it would be difficult to measure or even to demonstrate it, by means of the tape. A depressed part, too, may possess an amount of motion which would prevent Dr. Sibson's and Dr. Quain's chest measures proving of any avail. The hydrostatic neumatoscope is liable to the same objection. Callipers answer well, however. One extremity is placed on the scapular region, and the other upon the infra-clavicular region, the limbs bridging or arching over the upper aspect of the shoulder. The diameter of one side is taken, and then we proceed to take the diameter of the other. In phthisis, the diseased side ever tends to a reduction of diameter, and this we have ascertained by the employment of the callipers. Recently Dr. Nelson has improved the callipers. This instrument has a graduated scale, very serviceable in delicate and comparative measurements of the thorax.

TO MEASURE ANGLES AND CURVES OF THE CHEST.-The only instrument by which angles and curves are measured is the stetho-goniometer or chest goniometer, which I myself introduced into use. I have found it serviceable to measure deviations from the natural form of the chest, so common in all stages of phthisis. The measurement at different periods of the progress of the same case serves very accurately to indicate the degree of alteration, of increase or abatement of deviation, which may have taken place. The chest goniometer consists of two arms revolving upon a central joint, meeting at various angles as they are made to separate from or to approach each other. Connected with the central point of one of the arms is attached an arc duly graduated, and connected with the central part of the other arm is an in

dex, which moves along the graduated arc, as the arms are made to approach or separate from each other. The index points to the degree upon the arc, and denotes the angle formed by the meeting of the two arms. The parts which offer themselves most for measurement are the infraclavicular regions, and the junction of the sternum and the costal cartilages, and the junction of the costal cartilages and the ribs. In speaking of the alterations of the form of the chest in phthisis, I have already pointed out that flattening is a very frequent occurrence in the first stage of phthisis. In this case angles are not usually to be found, the alteration rather consisting of a loss of roundness, or of the normal curve. We have, therefore, in measuring this deviation with the chest goniometer, to take the curve, and not an angle. To take curves is more difficult than to take angles, which is extremely easy. Angles are by no means of uncommon occurrence at the articulations, indicated above, in the advanced periods of phthisis. These are easily measured. The same method is applicable to them as in the case of the angles of crystals, &c.

b

a

f

f

Stetho-goniometer, for measuring the inclination of different parts of the walls of the thorax

in cases of disease.

aa. The arms. b. The arc of a circle, graduated from 120° to 220°, the latter degree being on the left hand. c. The vernier, with an arrow at zero; the index of degrees. The vernier is divided into 12 equal parts, the whole being equivalent to 1° on the arc, or to 60'. d. Vernier arm. e. Joint. f. Inches and 10ths of inches, marked by lines, which when brought into line by bringing the two arms nearly together, would determine the 1st degree, if instead of an arc it had an entire circle.

At the conclusion of this work I have ventured to reproduce my papers on the chest goniometer, and on the deviations from the natural form of the chest, published in the "Archives of Medicine." The reader will there find directions for using the instrument and some of the results obtained by its employment.

TO MEASURE THE SO-CALLED VITAL CAPACITY.-For many years experiments have been made with different contrivances to measure the air exhaled in expiration.