586 General Symptoms. 



served this. Such sjanptoms would be most likely to arise in 

 cases of tumor-formation in the brain. 



Exag-geration of the tendon reflexes has been observed es- 

 pecially in cases of chronic encephalitis owing to the cutting out 

 of the inhibitory effect of the cerebral cortex. Contrary to wliat 

 is the case in man the exaggeration of the tendon reflexes may 

 be due to the cutting out of the cerebellum. A diminution of the 

 reflexes and especially of the skin reflexes is often seen in rap- 

 idly progressive acute encephalitis owing to the increased inhibi- 

 tion of the cortex. In complete loss of consciousness the skin 

 and pupillary reflexes are entirely lost; the tendon reflexes are 

 often entirely destroyed and the pupils do not react to light. 

 On the other hand, the pupils appear very contracted and react 

 only very slightly or not at all to light in simple cases of in- 

 creased intracranial pressure, although there is no loss of con- 

 sciousness. The alteration of the tendon reflex and the reaction 

 of the pupil may be observed as local s}^nptoms. 



The reflex test gives reliable results in animals. One distinguishes between 

 skin and tendon reflexes. The skin reflex is best tested by pricking the skin with 

 a needle or some other instrument, or often by the use of the percussion hammer, 

 and the tendon reflexes may also be tested with the percussion hammer or some 

 other hard object. 



The following skin reflexes may be tested. The reflex at the withers, a twitch 

 of the cutaneous muscle following stimulation of the skin over the withers. In a 

 similar way the skin reflexes over the shoulder, abdomen, sternum, and flank may be 

 tested. The latter test may be applied in all the domesticated animals, the first 

 two to the horse and ox, while the withers reflex as a rule is alisent in the ox. 

 The gluteal reflex is a muscular twitch due to a pin prick in the neighborhood of 

 the hip joint. The cremaster reflex may be tested by stimulation of the skin over 

 the inner condyle of the femur, the testicle on the same side being raised. In many 

 stallions and in dogs there is a scrotal reflex, the scrotal skin becoming wrinkled 

 when it is stimulated or when cold water is poured on it. Stimulation of the skin 

 of the perineum causes sinking of the croup, elevation of the tail, contraction of 

 the S2)hincter ani, and in many cases contraction of the muscles of the croup. 

 The contraction or spasm of the sphincter ani externus which is produced by 

 stimulating the skin of the orifice, or by the introduction of some solid body into 

 the rectum is described by some as the anus reflex. The hock reflex is a contraction 

 of the distal end of the biceps femoris and the semitendinosus induced by per- 

 cussion of the tuber of the os calcis. Eeflexes of the sole are normally seen in 

 carnivora only and in the hind feet. They may be produced by touching the skin 

 of the sole and are evidenced by spasmodic volar flexion of the toes. 



Schmidt observed spasniodic contractions of the muscles in the upper parts 

 of the legs set up reflexly in the following ways: pressure or percussion of the hoof 

 (pedal reflex), sudden pressure on the upper third of the pastern (pastern reflex), 

 on the inner side of the upper part of the metacarpus, and on the flexor tendons. 

 These reflexes must not be confused with withdrawal of the limb owing to pain. 



The skin reflexes include reflexes of the mucous membranes which are in some 

 instances very complicated, as for example the reflexes of swallowing, coughing, 

 and the bladder reflexes. The eye and conjunctival reflexes are simple. The pupil- 

 lary reflex is similar. This can be shown in animals in a satisfactory manner only 

 by stimulation by means of light. The pupil becomes narrower when light falls 

 on it if the transmitting media of the eye are uninjured. 



Among the tendon reflexes the patellar reflex is of considerable importance, 

 the arc being formed by the femoral nerve and its center. This reflex is not con- 

 stant in animals in the standing position. The animals must be placed on one 

 side and the upper hind ]eg is flexed to as great an extent as possil)le at the stifle; 

 for this help is necessary. The flexed leg being supported with the hand under the 

 hock, a smart blow is struck on median ligament of the patella causing extension 

 of the stifle joint in the backward direction. One must either wait until the animal 

 has ceased voluntary movements of the muscles attached to the patella or adopt 

 some means of distracting its attention from the legs. Under normal conditions 



