423 



That really such suhstances exiif, could be directhj piwed by tlie 

 fact lliat tlie wait solution, leaving llie heart after stimulation of the 

 vagus, contains substances, which lower the surface-tension of the 

 original salt solution, socalied capillary-active substances. On the 

 oilier hand we find that the surface-lension of lite salt solution, 

 coming from the heart af(er the sympathelic nerve has been siitnnlaied, 

 is slighll}' inci'eased '). Further it appeared that (he vagus- and 

 sympalliicus-substances wei-o able to neutralize each other in capillary- 

 active sense, i. o. w. they were able to neutralize each other's 

 influence on the surface-tension. 



1 shall not enter here into fiir-tlier particulars. It is an e8tablisl)ed 

 fact now, that as an etfect of stimulation of the vagus nerve, a 

 libeialion of vagus-substances takes place, and that on stimulating 

 the sympathetic nerve, synipathetic-sidtstances are set free. However 

 the nature of these substances has not yet been rlelermined ; perhaps, 

 at least with the vagus-stimulation, we lia\e to do x^itli clioliii- 

 compounds, which coo|i)erate with the potassinni. 



As for the method to determine the surface-tension of very small quantities of 

 fluids, we refer to two articles, which appeared last year^|. There it is shown 

 that a very simple apparatus will do for this purpose. By means of a torsion 

 balance, well-known to the clinicians, the force is deteiminecl which is necessary 

 to pull off a small platina-ring from the surface of tlie lluid which is to be 

 examined. 



The experiments discussed here, give rise to many (|uestions. So 

 the clinician will think of the bearing of these results on the nature 

 of vagotonia and sympathicotonia and will ask himself under which 

 conditions an excess of vagus- and sympathicus-subslances will exist 

 in the circidalion and influence different organs; and also he will 

 put himself the queslion how it will be possible to make this surplus 

 harmless for the body. 



The physiologist will ask himself whether the latent period and 

 the after-effect in vagus-stimulation can be explained by the time, 

 which is necessary for the liberating and the disappearing of the 

 vagus-substances; further he wants to know whether the vagus- 

 substances are specific for one and the same animal. And wlial will 

 be of interest both for the physiologist and the clinician is the 

 queslion : can we observe the same phenomena, seen in the frog. 



') See the article of Dr. Brinkman and Miss van Dam, in the Journal of 

 Physiol., still to appear. 



') R. Brinkman und Frl. E. van Dam. Miinch. Med. Wochenschr. 1921. S. 1550. 

 R. Brinkman, Arch. Néerl. d. Physiol. VII 1922, p. 258. 

 R. Brinkman- und Vv\. E. van Dam VIII, 1923, p. 29. 



