Physiology of Central Nehvous System 



5. We must also deprive the ganglion-cells of all specific 

 significance in spontaneous movements, just as wc Ikivo rlon*' 

 in the case of simple reflexes and instincts. Hy sj)()ntaneous 

 movements we mean movements which arc ai)parcntly deter- 

 mined by internal conditions of the living system. Strictly 

 speaking, no movements of animals are exclusively determined 

 by internal conditions, for atmospheric oxygen and a certain 

 range of temperature are always necessary in order to j)reserve 

 the activity beyond a short period of time. 



We must discriminate between simple and conscious sj)on- 

 taneity. In simple spontaneity we nmst consider two kinds 

 of processes, namely, aperiodic spontaneous processes and 

 rhythmically spontaneous or automatic processes. The rhyth- 

 mical processes are of importance for our consideration. 

 Respiration and the heart beat belong in this category. The 

 respiratory movements seem to indicate that automatic 

 activity can arise in the ganglion-cells, antl from this the con- 

 clusion has been drawn that all automatic movement6 are due 

 to specific structures of the ganglion-cells. Recent investiga- 

 tions, however, have transferred the problem of rhythmical 

 spontaneous contractions from the field of mori)hoK)gy into that 

 of physical chemistry. The peculiar qualities of each tissue are 

 partly due to the fact that it contains certain ions (Xa, K, Ca, 

 and others) in definite proportions. By changing these pro- 

 portions, we can impart to a tissue properties which it does not 

 ordinarily possess. If in the muscles of the skeleton th»- Xa 

 ions be increased and the Ca ions be reduced, the muscles are 

 able to contract rhythmically like the heart. It is only the 

 presence of Ca ions in the blood which prevents the muscles 

 of our skeleton from beating rhythmically in our body. As the 

 muscles contain no ganglion-cells, it is certain that the pow(>r of 

 rhythmical spontaneous contractions is not dut^ to the specific 



the contraction of one group of muscles noces.sitate.s the stretching of their antaRO- 

 nists the coordinated character of locomotive action seems to Inxnime IntelllKlMe 

 (1912). 



