( 825 ) 



Skin reflexes (ordened series) 

 (the average for the different condensators). 



Capacit}' 1 j Number ! Energ\- 



Voltage of i of each stimulus 



in ni.F. ' stimuli , in 10— i ergs. 



in tlio tables a minimum valno is obtained which is only sliuiiily 

 larger, namely an amount of 5 X 10^* ergs. 



The result got at the last root of the lumbal region wilh frogs 

 cannot be given in one table as the individual experiments differed 

 too much and have not been numerous enough to fix the average. 

 In a very sensitive preparation wiien the above mentioned condensator 

 of 0,00035 m. F. was used, a distinct reflex was obtained with a single 

 discharge of oidy 8,6 X lO-"" ergs, a result which shows clearly that 

 in the experiments of Mr. van Rp:ekum the reflex sensitiveness has 

 been considerably greater from the root than that from the skin. In a 

 single case there was even found a \aliie still three times smaller. 

 The above stated number however was not obtained accidentally 

 but represents a whole series of observations (12 in immber). 



By central stimulation of the cervical part of the nervus vagus 

 of a rabbit reflex-changes of the breathing were caused, which could 

 be registered by means of the aerodromograph '). The said reflex 

 consists according to the intensity of the stimulus 1. if stimulating 

 with very weak discharges in a slight increase of frequency of 

 breathing and in an increase of the rapidity of the current of air in 

 in- and expiration 2. if stimulating with somewhat greater discharges, 

 an increase of the rapidity of the stream of air notwithstanding 

 decrease of frequency 3. stimulating with sufficient great discharges 

 a distinct decrease in rapidity of the stream of air and frequency 

 both. If we only examine the result mentioned in the third 

 case as the reflex on which we want to base our measurements, 

 the results of the experiments may be taken together as follows: 



') H. Zwaardemaker und C. D. Ouwehand. Arch. f. Physiol. 19ÜI. p. 241. 



