( S26 ) 

 Breatli-reflexes. 



CONCLUSION. 



The reflex stimuli of diftevent kinds used as weak as possible on 

 cold- resp. warmblooded animals have in mini mo vei'y different 

 value. Thus one and the same effect was brought about by applica- 

 ting on the skin of a frog of an electric stimulus of 3,'J 5 X 10—* ergs 

 by a mechanical stimulus of 212 ergs, by a thermal stimulus of 

 11,5 mega-ergs and hj a chemical stimulus of 57 mega-ergs. So 

 of all these forms of stimulus the electrical is the most favourable. 

 It may be still more favourable when we let the stimulus act not 

 on the sldn but on a posterior lumbal root of the frog. Then 3 X 10 ^ 

 ergs is sufficient to cause a typical reflex and so the amount ap- 

 proaches to that wiiicli occurs with weak sensorial stimuli (light stimuli 

 vary in general between 1 X 10-'° as lowest and 6 X 10^ as highest 

 value; acoustical stimuli between 0,3 X 3~^ as lowest and 1 X 10' 

 as highest value ^). What liolds true for frogs, as a rule holds 

 true for mammals. From the nervus vagus there can be brought 

 about by central stimulation with an electrical stimulus of 0,17 X 

 1 0-4 ergs a very mai'ked change of breathing, whereas a few times 

 smaller value causes an indistinct but yet an unmistakable accele- 

 ration of breathing. Here also the minimum reflex stimuli have a 

 limit value of the order 1 X lO-** ergs. 



') Die physiol. wahrnehmbareu Energiewanderungen, Ergebnisse dei' Physiologic 

 Bd. IV. 1906. p. 423. 



(May 25, 1906). 



