370 D. OGATA AND SWALE VINCENT 



Thus, SO far as our experiments go, we are inclined to conclude 

 provisionally that among nerves of different categories there are 

 no essential qualitative differences of response, and the greater 

 the number of afferent fibers stimulated, the more marked is 

 the response of blood-pressure within a limited range of strength 

 of stimulation. 



6. VASOMOTOR REFLEXES FROM NERVE TERMINATIONS 



Several investigators have stimulated the nerve terminals 

 instead of the nerve trunk itself. 



WTien we apply a stimulus to a surface such as the skin we 

 should bear in mind that we may actually be stimulating either 

 the end-organs alone or these structures as well as the nerve 

 fibers, according to the mode of stimulation. Any physiologi- 

 cally appropriate stimulus, though mild, applied to the end- 

 organs would give rise to more highly effective impulses than 

 inappropriate ones. Thus the study of vasomotor reflexes in 

 response to stimulation of the sense organ with its most ap- 

 propriate stimulus is highly desirable. But even with other 

 kinds of stimulation we may learn much that is valuable, be- 

 cause any stimulus which plays a part in our normal daily life 

 comes usually through the end-organs on the outer or inner 

 surface of the body, and not by way of exposed nerve trunks, 

 as in the foregoing experiments. 



The skin, the mucous membrane of the nose, muscles, the in- 

 testine, and other abdominal organs were employed frequently 

 by previous investigators. We have selected the skin, muscles, 

 and the intestine as representative of regions containing differ- 

 ent modes of nerve endings. The stimuli used were mechanical 

 (incision, scratching, pinching, kneading), thermal (hot or boil- 

 ing water and cold water or lumps of ice), chemical (10 per cent 

 solution of sulphuric acid), and electrical (induction shocks of 

 various strengths). The animals (dogs) were under ether, 

 chloroform, or brain compression. 



The results of a first series are presented in the following 

 tables : 



