PLATE 2 



EXPLANATION OF FIGURES 



Fig. 5 A marked fall of blood-pressure which is apparently not due to in- 

 creased respiratory movements. Dog. 12 kilos. 9/5/191S. Ether. The left 

 sciatic nerve was stimulated. 



Fig. 6 An example of vasomotor reflexes upon weak (left) and strong (right) 

 stimulations. Same bitch as in figure 3. Thorax was very wide open in the 

 middle line to eliminate the influence from increased respiratory movements. 

 A weak stimulation caused a fall and a strong stimulation caused a rise of blood- 

 pressure. 



Fig. 7 Vasomotor reflexes under chloroform. Bitch. 7 kilos. 28/5/1918. 

 Thorax wide open. A weak stimulation produced a fall (left) and a strong 

 stimulation produced a rise (right) of blood-pressure. 



Fig. 8 Effects of weak and strong stimuli, respectively, under brain compres- 

 sion. Dog. IS kilos. 15/8/1918. Brain compression and artificial respira- 

 tion. Right ulnar nerve stimulated. The fall of blood-pressure increased at 

 first with the development of the strength of stimulus and then passed over to a 

 rise crossing a neutral point. • 



Fig. 9 Effect of frequency of stimulation upon vasomotor reflexes. Bitch. 

 13 kilos. 18/7/1918. Chloroform and curare. Right saphenous nerve was 

 stimulated. The frequency employed 1, 2, 5, 10, 20, 40, and 80 per second, re- 

 spectively, frorn left to right. The one per second stimulation caused a fall, 

 the two per second stimulation showed practically no effect, and the other stimu- 

 lations produced a rise. The maximum pressor response was reached at forty 

 per second stimulation in this case. 



Fig. 10 Stimulation of a sensory (saphenous) and a motor (a branch of the 

 femoral) nerve. Dog. 9 kilos. 10/10/1918. Brain compression and artificial 

 respiration. Stimulation of a sensory nerve gave a more pronounced fall than 

 that of a motor nerve. 



Fig. 11 Stimulation of nerves of the same category but of different sizes. 

 Same dog as in figure 10. The stimulation of a larger nerve (sciatic) produced 

 a more marked response than that of a smaller nerve (peroneal). 



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