342 Dr. K. Sassa. Effects of Constant Galvanic Currents upon 



obtainable in the peripheral nerve-muscle and in the flexor reflex preparation. 

 A few experiments were therefore made with these preparations, since the 

 exact data required could not be obtained from the literature. 



Method. — For the study of the reflex effects in an extensor muscle, the 

 vasto-crureus of the decerebrate cat has been employed. The animal was 

 decerebrated under deep anaesthesia with Sherrington's decerebrator. All the 

 hind limb muscles except quadriceps were paralysed by denervation or teno- 

 tomy. The popliteal, peroneal or sciatic was used as the afferent nerve. The 

 nerve was, though exposed previously, not actually isolated until everything 

 was in readiness to observe the effects of stimulation, in order to avoid any 

 changes resulting from exposure or injury to its vascular supply. The 

 movements of the lower limb were recorded by fixing the condyle of the 

 femur and attaching the tendo Achillis by means of a stout thread to one arm 

 of a crank lever ; the second arm, suitably weighted, functioning as a writing 

 point. The ascent of the myogram line in the figures means contraction of 

 the muscle ; descent means inhibitory relaxation. 



The constant current for stimulation was supplied usually from three 

 accumulators. They were connected with both terminals of a rheochord, 

 whose wire (of about 6 ohms resistance) was divided into 100 divisions. The 

 numbers on the figures denote those of divisions of the wire short-circuited to 

 stimulate the nerve. During the period marked by the downward notch in 

 the signal line the constant galvanic current is applied to the nerve. Time 

 below in seconds. 



The distance between the non-polarisable electrodes upon which the nerve 

 lay was usually 1'5 to 3 cm. and that from the ligated end to the distal 

 electrode was more than 2 cm. The nerve was kept moist with warm saline 

 or Kinger-Locke solution, or was sometimes enclosed in a glass tube, some- 

 what like the one described by Sherrington (11), in order to avoid evaporation. 

 The direction of the constant current is described as " descending " (D, in the 

 figures) when it flows in the afferent nerve from its cut end to the spinal 

 cord, and as " ascending " (A, in the figures) when opposite in direction. This 

 terminology is more reasonable in comparing the effects of constant current 

 in the reflex and the peripheral nerve-muscle preparations, as the current in 

 both cases passes through the nerve in the same direction with regard to the 

 effector organ. 



For the study of the reflex effects in a flexor muscle, the tibialis anticus of 

 either the spinal or decerebrate cat has been used. The spinal transection 

 was performed at the posterior end of the thoracic region. The nerve-muscle 

 preparation was also tibialis anticus with its motor nerve (peroneal) isolated 

 in the thigh. In these preparations, the distal end of the femur and tibia 



