FUNCTIONS OF THE SWEAT-GLANDS. 281 



divisions of the great motor system, the vasoconstrictor and 

 the excito-regulator nerves, and, furthermore, that all efferent 

 nerves were subdivisions of this system. If the sympathetic 

 nerves are the vasoconstrictor nerves, we are therefore bound 

 to account for any functional phenomenon witnessed attribu- 

 table to impulse-waves to the only remaining division: that 

 which we have termed "excito-regulator." 



The question as to whether such excretory nerves exist at 

 all has been the source of considerable controversy. Vulpian 

 recognized the existence of "sweat-exciting fibers," but he was 

 logically led to conclude, in order to account for the fluctua- 

 tions of activity actually witnessed experimentally and during 

 morbid states, that "secretion-moderating fibers" likewise ex- 

 isted. Foster, referring to both these nervous elements, says: 

 "Though the idea of a double nervous mechanism, augmenting 

 and inhibitory, governing the activity of the sweat-glands, is 

 a tempting one, there are at present no satisfactory reasons 

 for adopting it." We have just seen that the amount of blood 

 allowed to reach the sudoriferous glands or, to speak more 

 correctly in accordance with our views, the amount of blood- 

 plasma allowed to reach the secreting structures greatly in- 

 fluenced their activity; we might, therefore, consider the sym- 

 pathetic fibers as the "moderating fibers." Still, they not only 

 moderate the intensity of the process, but also likewise in- 

 crease it. The same line of argument applies to the term 

 "sweat-exciting fibers," and we are, therefore, obliged to re- 

 frain from using these terms, much as we are desirous of 

 preserving all we can of the nomenclature introduced by such 

 investigators as Vulpian. Indeed, both peripheral subdivisions 

 belonging, from our standpoint, to a single system, we cannot 

 attribute to one subdivision a physiological governing influence 

 over the other. As we view it, fluctuations affect both divis- 

 ions equally, the one flow of impulse-waves governing all 

 functions under their domination, and we look upon any 

 variation in this functional parallelism, balance, or equipoise 

 as pathogenic, whatever be its cause. 



That sympathetic fibers are distributed to these organs 

 is a recognized fact. All the experimental evidence adduced 

 section of the sciatic, including its sympathetic fibers; Vul- 



