to measure the strength of the hands, the two branches of the spring are firmly grasped, and brought as near together as the experimenter's strength will enable him to accomplish. The needle traversing the scale of kilogrammes indicates the strength of the hands. Some interesting results relating to the average strength of men at different ages, and of various weights and sizes, have been deduced by M. Quetelet, of Brussels, from numerous trials with this instrument. According to these experiments, a man twenty-five or thirty years of age is said to exert a force equal, on an average, to fifty kilogrammes, or 100 pounds.

SECTION 6. INSTRUMENTS REQUIRED FOR MAKING LOCAL APPLICATIONS IN DISEASES OF THE PHARYNX AND LARYNX.

Sir Charles Bell, MM. Trosseau and Belloc, and more recently Dr. Horace Green, of New York, were the first to resort to the practice of topical medication of the larnyx. The instruments required are, a tongue-depressor with a bent handle, by means of which the tongue can be firmly pressed down so as to expose the whole of the fauces and the upper edge of the epiglottis; and a whalebone probang, about ten inches long, bent in a curve, and having securely fastened to its extremity a nodule of fine sponge, about the size of an ordinary bullet. The solutions of nitrate of silver generally employed are of three strengths, consisting either of j, or Bij, or 3j, to 3j of distilled water. The method of introducing the saturated sponge is described somewhat thus by Dr. Hughes Bennett, in his treatise on Pulmonary Tuberculosis. The patient being seated on a chair and exposed to a good light, the practitioner stands on the right side, and depresses the tongue with the spatula held in the left hand. Holding the probang in the right hand, the sponge of which has been saturated with the solution, it should be passed carefully over the upper surface of the spatula, exactly in the median plane, until it is above or immediately behind the epiglottis. The patient must now be told to inspire, and as he does so, the tongue should be dragged slightly forwards with the depressor, and the probang thrust downwards and forwards by a movement which causes the right arm to be elevated, and the hand to be brought almost in contact with the patient's face. The operation of course requires dexterity, since the rima glottidis is narrow, and unless the sponge comes fairly down upon it, the aperture is readily missed.

The passage of the sponge into the proper channel may be determined by the sensation of overcoming a constriction, which is experienced when the instrument is momentarily embraced by the rima, as well as by the spasm and harsh expiration which it occasions. The application will generally require to be made about every other day, for a few weeks.

SECTION 7. THE OPHTHALMOSCOPE.

Attention has lately been directed in this country, by Mr. Spencer Wells and Dr. Wharton Jones, to an instrument invented by Dr. Helmholtz, of Konigsberg, for exploring the interior of the eyeball, in order to diagnose especially the morbid states of the vitreous body, the choroid, and retina. There are several modifications of the ophthalmoscope, but the most simple seems to be that of Coccius, which consists of a small plane mirror with a hole in its centre, so held that the light which falls on it from a lamp, concentrated by a double convex lens, is reflected into the eye to be examined: the observer looks through the hole in the centre. When the observed or observer's eye is short-sighted, a concave glass is placed before the observed eye. By means of this instrument, or one similar to it in principle, morbid changes in the retina could be distinctly recognized in the majority of the cases of blindness examined.

SECTION 8. THE SPECULUM UTERI, THE UTERINE

SOUND, ETC.

In the diagnosis of disease of the uterine organs we derive assistance mainly from four sources: 1, from the history and symptoms; 2, from a tactile examination-the touch: 3, from a visual examination with the speculum; and 4, from the use of the uterine sound. I shall only speak here of the instruments required in such examination.

The Speculum. The instrument is by no means of modern invention, assistance having been derived from its employment for many years; and although numerous arguments have been adduced in the present day against its use, from its abuse, yet still it is found—as before-impossible to diagnose many examples of uterine disease without its aid. Several varieties of speculum have been invented, and doubtless the ingenuity of mechanists will furnish more. The one that I am constantly in the habit of using is that known as Fergusson's, which consists of a cylinder of glass, silvered externally, and then covered with a thin layer of caoutchouc. It is ne

cessary to have four or five of these instruments of different sizes; they should also be furnished with movable plugs, projecting about an inch and a half from the uterine extremity, to facilitate their introduction. My colleague, Dr. Protheroe Smith, has invented a very useful speculum by which a visual and digital examination can be made at the same time. It is formed of two cylinders, the outer one being of metal, and the inner of glass; in the former is an oval opening, to allow of the passage of the finger. When the instrument is introduced, the glass tube is withdrawn if a digital examination be necessary, and the finger being then passed into the vagina posteriorly, enters the fenestrum and so reaches the os uteri. A third kind of speculum, which is often useful, is that made by Mr. Weiss, and which consists of two parts-a dilator and a cylinder. The dilator possesses three blades, which are expanded by turning the handle; when sufficiently dilated, the cylinder is introduced between the blades.

Either of these instruments can be readily introduced, and all the advantages to be derived from their use obtained, by placing the patient upon a couch, on her left side, with the knees drawn up-in fact, in the some position as for labor. The practitioner should be careful that no exposure of the person takes place, and must avoid anything approaching to force in passing the speculum up to the os uteri.

The Uterine Sound.-In the diagnosis of displacements of the uterus, or of tumors of this organ, this instrument-the invention of Professor Simpson-will be found invaluable. To give an idea of the uterine sound, it may be compared to a metallic bougie, curved so as to correspond with the natural direction of the uterine cavity, and fixed in a wooden handle, to facilitate manipulation. Its stem is divided into inches, and two-and-a-half inches from the point is a slight elevation, indicating the depth of the uterine cavity in its normal state. It may be introduced through the speculum, or merely along the finger passed up to the os uteri. I need hardly say that its use demands caution and gentleness; and although it may be feared that in unskilful hands it has produced abortion and other serious consequences, yet I believe that, when used by those capable of using instruments generally, it has never been productive of the slightest mischief, but, on the contrary, has proved a very valuable aid to the correct interpretation of disease.

Sponge-Tents.-The dilatation of the os uteri is sometimes rendered necessary by a suspicion of the existence of intra-uterine polypi. A series of sponge-tents should be em

ployed for this purpose, a small one being first introduced between the lips of the cervix uteri, succeeded by a larger one and a larger, until the amount of dilatation we desire has been obtained. Where rapid dilatation is required, Dr. Protheroe Smith sometimes uses an instrument very similar to a lithotrite for producing this condition. Great caution, however, is necessary in the employment of such an instrument.

CHAPTER III.

ON DISEASE.

SECTION 1. THE NATURE OF DISEASE.

DISEASE is known only by comparing it with the standard of health, from which it is a departure. The standard of health varies in different individuals, but speaking generally, it may be said that health consists in a natural and proper condition and proportion in the functions and structures of the several parts of which the body is composed. Physiology teaches us that these functions and structures have to each other as well as to external agents certain relations, whichbeing most conducive to their well-being and permanencyconstitute the condition of health. But from the same science we also learn indirectly, that function and structure may be in states not conducive to their permanency and well-beingstates which disturb the due balance between the several properties or parts of the animal frame; and these states are those of disease. Thus we learn from daily experience that in health the digestion of food is easy and comfortable. But when uneasiness, pain, flatulence, eructation, sickness, and the like, follow the taking of food, we know that the function of digestion is changed from the healthy standard—that it is diseased; and if this diseased function continue long, in spite of remedies which usually correct it, and if on examining the abdomen we find at or near the epigastrium a hard tumor, which anatomy teaches us is not there in health, we know that there is also diseased structure. We find then that there is disease of function, known by its deviation from a physiological standard; and a disease of structure, which we recognize by an anatomical standard. These varieties of disease are commonly combined, structural disease without disordered function being rare; while functional disease is often accompanied or at all events followed-by change of structure.'

1 Dr. C. J. B. Williams's Principles of Medicine. Second edition, p. 2.

Functional Diseases.-The leading features of this class of disease may be briefly spoken of in connection with the two most important systems of the body-the vascular and the

nervous.

In the vascular system there may be an excess of blood, either generally or locally. Excess of blood generally, causes plethora, with often increased natural secretions, increased functional vigor, irregular actions, excessive-and perhaps morbid growths. Locally increased supply of blood merely gives rise to excitement, or to congestion, with oppression of the congested organ. A defective supply of blood may also be general or local; when general, producing anæmia; when local, causing defective secretions, loss of energy, and a tendency to disordered actions. The supply of blood may likewise be perverted, and thus produce disordered function.

In the nervous system we equally notice excessive, deficient, or irregular distribution of nervous force, giving rise to temporary loss of health. Nervous disturbance may exist alone, or may be combined with vascular irregularity, producing various affections of nutrition, secretion, absorption, evacuation, muscular motion, or of the sensorial offices, or of the intelligence and will. But, as before observed, functional derangement seldom continues long without producing,

Structural Diseases, which may be comprehended under the three heads of increased, diminished, and perverted nutrition. Dr. Williams (op. cit. p. 345) has arranged the elements of lesions of structure in a table, essentially similar to the following.