Such are the details which we may gather from a simple inspec tion of the parts. Palpation gives us information of no less value. In the first place we are enabled to detect modifications in consistence of the affected group of muscles. Under normal conditions the tis sues which we are now considering have a very characteristic elas ticity and firmness all their own, but in disease this firmness may be increased or diminished in more or less marked degree. Sometimes a sensation of resistance, which may amount even to hardness, is im parted to the touch; at other times, on the contrary,. the muscle is soft and gives to the examining finger an impression almost exactly like that imparted by adipose tissue. The degree of softening may at times be even more pronounced, and the condition may go on to the formation of an abscess, when fluctuation will become manifest. Changes of temperature are frequently appreciable to the hand as well as by the thermometer. In acute myositis the parts are hot and burning, while in certain chronic affections on the other hand, in atrophic conditiong for example, a reduced local temperature has oc casionally been noted.
In order to complete this enumeration of the facts to be learned from physical exploration, we ought perhaps to mention direct micro scopical examination of the diseased muscle. In certain cases of pe culiar interest, we may extract a little piece of muscular tissue by means of a harpoon and examine it under the microscope. That is, however, a point of purely scientific interest, for the method is sel dom of any practical clinical utility.
Functional Signs.—The two most frequent and most symptoms are lassitude and pain. When the muscular system is affected the patients experience difficulty in movement, they complain of great weakness and heaviness in the limbs. I believe that in most acute infectious diseases the initial lassitude that is felt is often an expression of muscular inflammation. As the condition increases in severity pain is felt; the affected parts may be located by the tender ness elicited by pressure, or else the patient himself locates the disease by the more or less severe pain, occurring independently of pressure, in one or the other part of the body. This pain may be of such inten sity as to prevent absolutely all movement of a limb or of the seg ment of a limb. Functional impotence is therefore a result of the pain. But this may equally be due to degenerative changes. In pseudo-hypertrophic muscular paralysis, for example, the time comes when the lesions are so advanced that the patient is incapable of movement and is obliged to keep the bed. The same thing also occurs in lead palsy,—if it be admitted that the poison in this con dition acts directly upon the muscle, the tendency now being rather to consider the toxic action as affecting the nerve terminations, to the lesions of which the paralysis is due.
As regards the functional symptoms nervous and muscular affec tions are often closely related, and in certain cases it may be difficult to determine the part taken by each of the two elements in the pro duction of the symptoms. I do not propose to enter upon the domain
of the pathology of the nervous system ; hence in speaking of muscu lar contraction, a most common symptom, I shall concern myself only with that arising directly and solely from disease of the muscle itself. This condition of hardness and rigidity is occasionally produced as a result of inflammation—the best example which occurs to me being the affection of the sterno-cleido-mastoid muscle known as torticollis. From some cause or another this contraction may disappear and the function of the affected muscle be restored to the normal. It is not the same, however, with true contracture. This symptom is the ex pression of a sclerotic lesion and is consequently of much more sombre prognostic import than is simple contraction.
In the group of functional signs we may conveniently study the modifications of electrical contractility. By this term is meant the property which the muscle possesses of contracting under the in fluence of the electric current. It is necessary here again to distin guish between the direct action of the electricity upon the muscular tissue itself and that produced by the intervention of the nervous con ductors. Duchenne and Remak have contributed largely to our knowledge of electrical muscular contractility. More recently Legros and Onimus have taken up the study of the subject and have pre sented conclusions of very great interest. It is probable that the last word on this subject has not yet been said, but however this may be, we are able by this mode of examination to obtain very valuable data concerning the functional capacity, the contractile power, of the muscle.
In conducting this method of exploration we may make use of two of the forms of electricity, continuous and interrupted currents, studying thus the galvano- and the farado-muscular contractility.
Whatever may be the kind of current employed the technique re mains the same. The object is to influence the muscle directly, avoiding as far as possible all outside influences. That, it is hardly necessary to say, is an unattainable ideal, for it is impossible, under normal conditions, to dissociate completely the electrical excitability of the muscles and that of the nerves. This should not deter us, when studying the properties of muscular tissue, from making every effort to approach as near as may be to the ideal. It is to this end that it has been proposed to employ very fine needles as electrodes, one connected with the positive and the other with the negative pole. We might indeed obtain very exact results by inserting one of these needles at one of the points of insertion of the muscle and the other at another, and making the current pass between them, but this is a method that is not practically applicable.