TRANSACTIONS OF SECTION I. 817 



therefore tecomes much distended. Periods of large ventricular diastoles and 

 systoles and large auricular systoles thereof alternate with others of small ventri- 

 cular movements and weak systoles and great distension of the auricle. 



These periods are best seen in the beginning of the irregular stage of poisoning 

 with substances of the digitalis group, where the irritability of the ventricle has 

 been increased just enough to cause a slightly more rapid rhythm than that supplied 

 from the auricle. As the irritability is further augmented, the periods become 

 shorter and less distinct. I have observed this periodic variation once (under 

 caffein), where Rw = R« — 1. 



Occasionally another form of rhythmic irregularity occurs, in which Ry = 

 R« — 2. In this case a secondary period occurs during the primary one, and the 

 whole period is distinctly less regular. When Ry = R« — 3 the periodic variations 

 become still more difficult to trace, and when the divergence between Rj; and Ra 

 is still greater all appearance of periodicity is lost. 



In the normal lieart the position of the As in the ventricular cycle varies from 

 the first third of the diastole to the extreme end of the diastolic pause, and may 

 even be prolonged into the ventricular systole. The efficiency of the heart must 

 be atfected by this factor, least work being wasted when the auricular systole 

 corresponds with the first part of the ventricular relaxation, and a considerable 

 amount of energy being expended in the mutual opposition of the auricle and 

 ventricle, when the systole of the former overlaps into that of the latter. 



Report on the Physiological Effects of Peptone and its Precursors. 

 See Reports, p. 531. 



7. The Absorption of Serum in the Intestine. By E. Waymoutii Reid, 

 Professor of Physiology in University College, Dundee. 



Heidenhain ^ demonstrated the fact that the water, organic and inorganic 

 solids of serum introduced into the intestine, are absorbed. 



The experiment was devised in support of the theory that intestinal absorption 

 is possible under conditions in which osmotic transfer is excluded. 



It was found that even inspissated serum is absorbed, and that at no time 

 during the course of the experiment is a serum with a lower percentage of sohds 

 than that of the experimental animal found in the loop of gut, thus meeting the 

 objection (so far as the absorption of the solids is concerned) that in such cases 

 the serum introduced into the gut is diluted by water from the succus entericus. 



Heidenhain omitted to measure the hydrostatic pressure on either side of the 

 intestinal membrane, so that the possibility of the result being due to filtration 

 was not excluded; and, indeed, the ancient filtration theory of Lieberhuhn"^ has, 

 with the necessary modern histological modifications, been revived of late by 

 Hamburger.^ In the experiments now described, the animal's own serum (obtained 

 by the centrifugal machine) was introduced into a loop of its intestine, and the hydro- 

 static pressure in the cavity of the experimental loop, and in a mesenteric vein 

 proceeding from a control loop, filled with ' normal saline ' solution, observed 

 (iontinuously during the course of the experiment. 



As will be seen from the cases quoted, water, organic and inorganic solids, are 

 absorbed against considerable excess of hydrostatic pressure in the blood-vessels. 

 (Since the velocity of the blood stream in capillaries is low, it is taken for granted 

 that the pressure in the capillaries of the intestinal villi is not lower than that in 

 a mesenteric vein at the border of the gut.) 



The experiment presents practically the same features iohen all the lacteals 



' Pfiiiger's Archiv, 1894, Bd. Ivi. s. 579. 

 * JJefahrica et actione villorum, 1757. 

 ' Du Bois-Reymond's Archiv, 1896, s. 428. 



1897. 3 G 



