fibre being .002 to .003 of a millime- right ventricle the blood goes to the tre. Electric currents are sent lungs for aeration, back into the left through a patient from right to left auricle, thence into the left ventricle arm, or from right arm to left leg, and thence throughout the body. The or from left arm to right leg. Each impulse of the heart to contract lead gives a different curve, and while starts in the auricle, and it has been the various electrocardiograms, as the shown by His, Jr., that the only concurves are called, either physiologic necting link between the auricles and or pathologic, are not all fully under- ventricles is a single bundle of fibres stood, because the actual course of usually called "His's bundle." Near events is not yet clear, certain essen- the junction of the superior vena tial facts are evident. The curves cava with the auricle, there lies in show the auricular and ventricular the human heart some specialized contractions and pathologic variations muscular tissue, which seems to be therein, as well as the normal con- the remnant of the original cardiac duction or abnormal lack of conduc- tissue of the most primitive hearts. tion of contractile impulses in the In this specialized tissue the heart muscle fibres. beat seems to arise and thence it spreads on one side into the muscular tissue of the auricle, and on the other side by means of His's bundle, down the septum between the right and left ventricle of the heart, following the fibres of the bundle out to the lower end of the right and left ventricles. Normally the contracting impulse passes down with even regularity from auricle to ventricle; but injuries or disease in the fibres of His's bundle causes disturbances in the passage of the contracting impulse which vary from simple retardation of the impulse to blocking it off completely. It has been found that one, two or three impulses from the contracting auricle may occur, and only one go through to the ventricle, or the heart block may be complete and no impulse go from auricle to ventricle. Auricles and ventricles may then beat independently of each other. In the fibres of His's bundle, before they separate to go to each ventricle, there seems to originate a contractile impulse when the auricular impulse ceases to arrive and stimulate them. Irregularities of the heart's action have thus been found to arise from disturbance of the conduction of the contracting impulses, or they may be due to irregularities To appreciate these advances in of contracting impulses arising in the medicine, it must be remembered that auricle or in the ventricle, independthe heart is a four-chambered organ, ent of the auricular action. In other divided into a right and left side, cases the rhythm of contraction may without direct communication be- be arising from impulses coming tween these sides. The two upper from either auricle or ventricle in difchambers, the auricles, drive the ferent rates of rhythm,-so that any blood directly into the two lower given contraction may be from the chambers, the ventricles. From the impulse either from either auricle or Previous to this the profession was dependent upon the stethoscope and manual percussion to obtain their knowledge of the normal heart and the variations from the normal which the various morbid processes in the heart produced. It was possible to say which valves were damaged, and to gauge with a fair amount of accuracy how great the damage might be, judging from the relative dilation and hypertrophy of the walls of the various chambers of the heart. But an accurate knowledge of the conditions of the muscular wall of the heart which was evidently the important portion of the organ as far as its mechanical efficiency was concerned, could not be obtained. The graphic records obtained from the jugular vein showed that a record could be obtained of what occurred within the auricle of the heart, and the rate of transmission of the contracting impulse from the auricle to the ventricle could be measured, and that in comparing this venous record or phlebogram, as it is called, with one from some artery, such as the carotid or radial, an intelligent interpretation of various irregularities of the heart beat could be made out. ventricle, or from both simultane- the curves obtained in experimental ously. laboratory work and have added These graphic records bring the greatly to the diagnosis and treatclinical study of the heart's action ment of the various morbid changes within the range of comparison with occurring in the human heart. SURGERY ADRIAN V. S. LAMBERT Fractures. During the year no great discovery has been made in surgery, but a decided advance has occurred in the science as a whole. The treatment of fractures of the long bones has become more radical, and the operative reduction is more generally used. Surgeons are becoming convinced that the most satisfactory results can be obtained in many cases by following the technique given by Lane of London a number of years ago. The technique consists of operating on the fractures immediately after injury, or at least within a few days, and exposing the ends of the fragments, (then under direct vision) reducing the fracture perfectly, and maintaining the reduction by means of steel plates which are screwed on to the bones. The wound is closed, and the screws and plate remain permanently in situ, the bone healing over it. This method is best adapted to transverse fractures of the shaft of the tibia. It is also the best method in fractures of the shafts of both bones of the forearm preventing as it does the vicious cross union, and it has been employed in cases of old ununited fractures with some excellent results. Transfusion of blood is now done in a greater number of conditions. Formerly it was used in combating the results of severe hæmorrhage and in some hæmorrhagic conditions, notably the bleeding of the new born, but now it is used in overcoming the severe anæmic state in the cachexia of malignant disease in order to allow the patient to stand the operative procedure necessary for the removal of the growth. It has also been used in certain of the anæmias with benefit. The vascular anastomosis is accomplished by means of one of the mechanical aids or cannulæ, usually that of either Crile or Elsberg. Administration of Ether.-A new apparatus for the administration of ether by the intratracheal method of Auer and Meltzer has been perfected by Elsberg of New York. This apparatus has simplified and rendered safe the administration of ether on this principle. The method consists of delivering the ether vapor directly into the trachea by means of a tube passed through the larynx. The tube is smaller than the chink of the glottis and the exhaled air and ether vapor escape alongside the tube. This bids fair to replace the various cabinets for operating on the thoracic cavity. Although primarily designed for operations on the viscera contained in the thoracic cavity, it nevertheless has proved of great value in operations about the face and neck. The constant current of ether and air escaping at the intratracheal tube is of great use in operations within the mouth and nasal cavity, and for cases of intestinal obstruction with vomiting. addition it is said to have fewer ill effects afterward, as vomiting and pneumonia. In new Internal Hydrocephalus.-A operative procedure for the cure of internal hydrocephalus has been reported by Andrews of Philadelphia. A glass rod is inserted through a hole into the lateral ventricle. The glass rod remains in place and drains the ventricle. The skin is united over it. Esophagoscopy, gastroscopy, are still more or less in the experimental stage. Numerous new instruments have been invented. They are all made on the principle of a hollow tube' with electric light at the lower end to illuminate the structures below the end of the tube. Janeway and Green report having been able to see and recognize cancer of the esophagus and of the stomach when the growth is situated at or near the region of the cardia. They are also able to remove for microscopical examination small pieces of tissue by means of a pair of long biting forceps passed down through the tube. In Germany, Lexer and others report that they have made a new œsophagus out of jejunum transplanted beneath the skin of the sternum, and connected with the œsophagus in the neck, by means of an artificially formed tube of skin formed by infolding the skin on the chest. It is said to functionate perfectly and is used on cases in which the œsophagus has been destroyed by the action of caustics and corrosive substances. LIII. JANEWAY and GREEN.-Surgery, Gynecology and Obstetrics, Vol. XIII, p. 245. Papillary Growths of the Urinary Bladder.-Bier of New York has developed a technique for the cure of papillary growths of the urinary LEXER.-Centralblatt f. Chirurgie, 1911, bladder by means of the Oudin high p. 55. XXXII. ENGINEERING THE PROFESSION OF ENGINEERING WILLIAM KENT those concerned with the development and operation of mines," electrical engineer" to those who specialized in the generation and transmission of electrical currents, etc. The "profession of a civil engineer" | machinery, "mining engineer" to was defined by Thomas Tredgold, in the charter of the Institution of Civil Engineers, in 1828, as "the art of directing the great sources of power in nature for the use and convenience of man, as the means of production The engineering profession has now and of traffic in states both for exter- become subdivided into a great numnal and internal trade, as applied in ber of special branches, each with its the construction of roads, bridges, own name, such as sanitary, municiaqueducts, canals, river navigation pal, hydraulic, chemical, architecand docks, for internal intercourse tural, refrigerating, illuminating, and exchange, and for the construc-heating and ventilating, etc., and tion of ports, harbors, moles, break- many of these branches have large waters and lighthouses, and in the art of navigation by artificial power for the purposes of commerce, and in the construction and adaptation of machinery, and the drainage of cities and towns." and growing national societies of their own. A rigid scheme of classification of the several branches is difficult to make, since many of them overlap one another, but the following may serve as a tentative classification: An engineer is one who has first studied the fundamental sciences that lie at the basis of all engineering, namely mathematics, drawing, physics, chemistry, mechanics, and the properties of materials of construction, and has afterward specialized in one of the three chief divisions of the engineering profession, which are defined below. In 1828 the term "civil engineer" meant an engineer in civil life-not a military or naval engineer. At that date a civil engineer was a man like George Stephenson, who could lay out and build a railway and who could design and construct a bridge, a locomotive, or a pumping engine, and direct the "great sources of power in nature" towards any of the objects named in the broad definition of Tredgold. With the growth of the mechanic arts, however, it became necessary for engineers to specialize their work, and the need arose for new prefixes to the general title "engineer," such as "bridge," "marine," etc. In this way the meaning of the Mechanical Engineering.-Changtitle "civil engineer" gradually being the shape and location of matecame restricted to denote a man de- rials. The design, construction, invoted to the construction of perma- stallation and operation of machinnent structures, such as roads, ery. The generation, transmission bridges, canals, docks, etc., and the and utilization of power. title "mechanical engineer" was apElectrical Engineering.-The study plied + who designed and built of electric currents and the design Civil Engineering.—Changing the earth's surface. Roads, streets, bridges, tunnels, foundations, masonry and metal structures, rivers, harbors, docks, railway permanent way, water-supply, sewerage, etc. and construction of machinery for | Refrigerating.—M. generating, transmitting and using Automobile.-M. them. The electrical engineer is pri- In addition to the specialization of marily a mechanical engineer, but his special field of electrical theory and design is usually not included in mechanical engineering. The numerous other specialties in engineering are either subdivisions of one or other of these three, or else are combinations of selected parts of two or more of them, some of them also combining knowledge of other sciences and arts such as geology, chemistry and architecture. Denoting the three main branches, civil, mechanical and electrical engineering respectively by the letters C., M., E., and geology, chemistry, bacteriology, etc., by abbreviations, we may construct the following list showing the relations of the several subdivisions and special branches of engineering to the main branches: Mining.-C., M., E., Ch., Geol. Chemical.-M., E., Ch. Metallurgical.-M. E., Ch. engineering there has in recent years been a great expansion of its field. Formerly an engineer's chief work was finding how to do things with materials of construction and with the forces of nature. Now it is how to do things in a larger and better way, with greater economy of fuel and other material and of time and labor. Conservation of resources, saving of waste products, organization, system, and efficiency, are now the watchwords of the engineer. He has become a business man, a political economist. The new development has given rise to new definitions of engineering, such as "making one dollar do the work of two dollars," "overcoming the resistances of nature including human nature," and to a new specialization by an as yet small group of consulting mechanical engineers who have been variously styled "efficiency" engineers and "scientific management" engineers. Their work has chiefly been in connection with factories, and it includes every economical problem of the factory, such as the selection and plac Sanitary (San.).-C., M., Ch., Bact. ing of machinery, the efficiency of Municipal.-C., E., San. Heating and Ventilating (H.)-M. its operation, the method of handling material, the investigation of methods of doing work, "motion study," compensation of the workmen, system of management, cost accounts, etc. (See XXXII, Industrial Management.) CIVIL AND HYDRAULIC ENGINEERING LICENSING ENGINEERS During the past year there has been a nation-wide movement to license engineers. In several states bills have been introduced requiring anyone practicing engineering to pass an examination before an official board, which would be authorized to grant licenses to qualified persons. In most of these bills the present practice of engineering would be a sufficient qualification, but in future it is intended that the engineer be placed on the same basis as the doctor and an the lawyer as regards official recognition. Some bills prescribed annual license in addition to the original fee. Only two or three of such bills became law, and the opposition among the profession has been 80 great that it seems improbable that any general passage of such laws will prevail. The difficulty in establishing a criterion of ability, the necessity for an engineer to procure licenses in many states, and the hardship of an annual tax are the principal arguments against the requirement of licenses. |