(Fromn the Department of Physiology of Columbia University at

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Solomon Newman
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1 AN APPARATUS FOR ARTIFICIAL RESPIRATION AND FOR OTHER PURPOSES. BY JOHN T. HOYT. (Two Figures in Text.) (Fromn the Department of Physiology of Columbia University at the College of Physicians and Surgeons, New York.) THE purpose of the apparatus described in this paper is to produce either a blast of air, a vacuum, or artificial respiration of any desired frequency and amplitude. For the last-named purpose it has been used satisfactorily upon a calf weighing 200 pounds ( kilogrammes), and upon dogs, cats, rabbits, rats, mice, and pigeons. It consists of an air-pump, an air-tank, and an appliance which causes the air to enter and leave the lungs with a rhythm variable at will. The Pump. The pump is mounted upon a table, and consists of a single upright hollow cylinder of cast-iron, within which rises and falls a piston without valves. This is driven by a crank turning in a crank-box which moves to and fro in the horizontal slot of the cross-head of the piston-rod. The crank is set in the middle of a horizontal shaft which has a fly-wheel at one end, and at the other tight-and-loose pulleys, by means of the belt of which the pump is worked by the main shaft of the laboratory, this main shaft being driven by steam or by electric power according to circumstances. Above the piston, the cavity of the pump has both an inlet and an outlet for air, each guarded by a puppet-valve. Below the piston, also, the pump has both an inlet and an outlet for air, each with its puppet-valve. By a simple device each outlet can be made to communicate with the outer air, through a cock, independently of the other outlet, or, the two cocks having been closed, to communicate with a vertical channel, common to both outlets, in the thickness of the wall of the cylinder. From this common channel a single outlet leads to the outer air through a cock. When this common

2 RESPIRATION APPARATUS. channel is in use, through its single outlet a continuous blast is delivered by the pump, inasmuch as both the ascent and descent of the piston expel air into the common channel and into that only. When communication between the two outlets has been cut off, and the two inlets have been connected each with one branch of a Y tube outside the pump, of which Y tube the stem leads to a receiver to be exhausted, the pump exerts a continuous suction, inasmuch as air from the receiver, and from that only, is drawni into the pump by both the ascent and the descent of the piston. When there is no communication either between one outlet and the other or between one inlet and the other, the space above the piston and the space below the piston become two wholly independent chambers, each with its own inlet, outlet, and valves. Under these conditions the pump may be nmade to exert an intermittent suction below the piston, and at the same time to deliver an intermittent blast above the piston, or vice vers4. When used solely for producing a blast, this pump, with its own shaft revolving 70 times a minute, will deliver, in 1 minute, 95-2 litres of air, and will generate a pressure of *7 kilogramme to the square centimetre (10 pounds to the square inch) readily and without strain. When used solely for suction, the pump, at 70 revolutions a minute, will produce in 1 minute and 40 seconds a negative pressure of centimetres (27X75 inches) of mercury in a tank holding litres. The Tank. The air-tank is an upright hollow cylinder of galvanized iron, 36 inches (0 914 metre) high and 12 inches (0'305 metre) in diameter, arranged to stand on the floor. In its upper end are four tubulures without valves. These tubulures are the inlet, the outlet, the opening for the pressure-gauge, and the opening for a small adjustable safetyvalve. When used for artificial respiration, this tank is connected by very thick-walled rubber tubing with the pump and with the appliance for regulating the breaths. The Breath-regulating Appliance. (See Figs. 1 and 2.) The essential part of this is constructed on the principle adopted by Prof. J. R. Ewald, in designing his " Luftcommutator." The appliance now to be described consists of a low right cylinder of bronze, which I Ewald, J. R.: Archiv f. d. ge8. Physiol., XXxI, p PH. XX[VII. 4 49

3 50 J. T. H[OYT. revolves about its own vertical axis within a closely-fitting cylindrical bronze box or "sleeve," which is fixed to the table. The top and To TRACHOaI'-M TrUE. Z 'FROM -TANK ToTRACHEOroMY- TUBE NO.1 Fig. 1. bottom of this sleeve are pierced by the axis of the revolving cylinder, to which axis they afford bearings. The fixed cylindrical sleeve is pierced on its convex surface by four horizontal tubulures, each normal to the cylinder and placed midway between its upper and lower ends. These tubulures are separated by equal intervals of 900. The convex surface of the revolving inner cylinder shows four apertures, each placed midway between the top and bottom of this cylinder. These apertures are separated by equal intervals of 900. At a certain moment, therefore, of each revolution of the inner cylinder, each of its four apertures corresponds with the inner opening of one of the four tubulures of the fixed sleeve. The four apertures in the inner cylinder are the mouths of two entirely separate horizontal canals bored in the otherwise solid bronze. Each canal is bent upon itself at an obtuse angle, so that its two mouths are 900 apart. It follows from the foregoing description that, when the inner cylinder is revolving regularly, its canals will connect a given tubulure of the sleeve, at regular intervals, first with the tubulure on its immediate right, and then with the tubulure on its immediate left, or vice vers4. Therefore, if the given tubulure be receiving air continuously

4 RESPIRATION APPA RA TUS. from the tank and pump, it can deliver it at regular intervals through the revolving cylinder and the aforesaid two tubulures of the sleeve to the tracheae of two animals in succession. The expiration of each animal may be provided for partly by the well-known device of a sideopening in its tracheotomy-tube, and partly by means of the fourth tubulure of the sleeve, through which fourth tubulure the trachea of each animal communicates freely for a while with the outer air, by means of one of the canals of the revolving cylinder, not long after this animal has ceased to.receive an inspiratory blast. 51 Fig. 2. By cutting each opening of each canal of the revolving cylinder to the form of an irregular lozenge, provision may be made for a more or less gradual beginning and ending of each inflation of the lungs; and by the same means the relative lengths of inspiration and expiration may be fixed. No attempt, however, has been made to provide for varying these relative lengths at will, as may be done in using the "Luftcommutator" of Ewald. 4-2

52 J. T. HOYT. The amount of air delivered to a tracheotomy-tube at each blast can easily and quickly be altered, by means of the safety-valve and escape-cock.

5 52 J. T. HOYT. The amount of air delivered to a tracheotomy-tube at each blast can easily and quickly be altered, by means of the safety-valve and escape-cock. The main-shaft of the laboratory drives the revolving bronze cylinder by the agency of a counter-shaft fixed to the table upon which stand both the pump and the sleeve of the revolving cylinder. The strong bronze vertical axis of this cylinder is joined at the centre of its upper end to the centre of the under surface of a broad horizontal friction disk, also of bronze. Cylinder, axis, and disk, are kept in regular revolution by the action upon the disk of the convex surface of a small revolving "brush-wheel" driven by the counter-shaft. Of this brush-wheel the bearing surface is of leather, and the brush-wheel itself can be fixed at any point of its own horizontal steel shaft, which is supported at the proper distance above the disk and passes over the centre of the latter. This horizontal steel shaft bears at one end a cone-pulley with six grooves, which pulley is, by a round belt, connected with and driven by a pulley of one groove mounted upon the countershaft upon the table. By means of the construction just described, the regular revolution is secured of the bronze cylinder with its two canals. Without the revoluitions of the shafting being stopped, the revolutions of the cylinder can be made suddenly to cease, or to recommence, by turning a handle which slightly lowers the disk away from the brushwheel or lifts it into contact therewith. Also by mneans of the construction just described, the rate of artificial respiration can be very delicately varied within wide limits, on the principle employed in the kymograph of Ludwig to vary delicately the speed of revolution of the drum. The main-shaft of the laboratory and the counter-shaft on the table revolve each at an unvarying rate; but, by the use of round belts of different lengths, the counter-shaft can impart any one of six speeds to the cone, shaft, aud brush-wheel of the respiratory appliance itself; while, by the shifting of the brush-wheel along its shaft to a point nearer to, or farther from, the centre of the friction disk, any one of the six speeds aforesaid can be considerably and delicately varied. Practically, any rate of respiration can be secured between the limits of 10 and 120 breaths a minute. In describing the foregoing apparatus, no effort has been made to point out all the possible applications, even to artificial respiration alone, of its various powers. So far as it has yet been applied it has been found effective.

Introduction to I.C Engines CH. 1. Prepared by: Dr. Assim Adaraje

Introduction to I.C Engines CH. 1 Prepared by: Dr. Assim Adaraje 1 An internal combustion engine (ICE) is a heat engine where the combustion of a fuel occurs with an oxidizer (usually air) in a combustion