Physiology. — ''On the effect of H^O^ on the peristalsis of the 

 isolated intestine." By Prof. Hamburger and E. Brouwer. 



(Communicated in the meeting of October 27. 1917). 



After one of us had demonstrated that oxjgen as H^O, — unlike 

 free oxygen — stimulates the white blood corpuscles into a more 

 active phagocytosis ^), it seemed of importance to examine the way 

 in which other vital processes are affected by these two forms of 

 oxygen. For this purpose we have experimented on the isolated 

 intestine. 



These experiments were carried out with rabbits' intestines. After 

 the animals had been killed by a blow in the neck or by opening 

 the carotid, the belly was quickly opened, a jejunum convolution 

 was taken out and pieces of it were suspended according to the 

 method of Magnus, in a heated TYROOE-solution, through which 

 oxygen was led. This results, as we know, in regular rhythmical 

 intestinal movements if the gas beads pass in a slow continuous 

 current through the fluid ^). 



First we investigated how a modification of the oxijgen current 

 affected the contractions. We found that even a considerable increase 

 had not the slightest eject upon the curve. 



Of course we do not wish to infer fi-om this that oxygen is not 

 of the utmost importance for the function of the intestine. The 

 reverse was already discovered by Magnus in 1904: when the 

 oxj gen-current is stopped, the contractions cease after a state of 

 excitement — -"einer dyspnoischen Erregung" — which was also 

 noticed by Hamburger with regard to the phagocytes '). 



After it had become evident that an increase of oxygen beyond 

 a certain minimum took no effect we have added H^O,, and this 

 always brought about an increased action of a shorter or longer 

 duration. Mostly it consisted in the tonus being considerably heigh- 

 tened, whilst the contractions grew smaller (fig. 1); in other cases 

 the tonus-increase was less great, but the oscillations of the separate 

 contractions had become much greater. The frequency remained 



1) H. J. Hamburger, Internat. Zeitschr. f. physik. chera. Biologie 2, 255 (1915). 



Ï) Magnes. Pfiüger's Archiv 102, 125. (1904). 



^) H. J. Hamburger, Internat. Zeitschr. f. physik. cliem. Biologie 2, 249 (1915). 



61 

 Proceedings Royal Acad. Amsterdam. Vol. XX. 



