784 



SCIENCE. 



[N. S. Vol. II. No. 50. 



demonstrations and papers (Chairmen, 

 Profs. Eutherford and Heger) . 



Dr. W. His, Jr. (Leipsic), discussed the 

 mechanism of the heartbeat. He sup- 

 ported Engelmann's view of the purely 

 muscular propagation of the contraction 

 wave, not only in auricles and ventricles 

 separately, but from auricles to ventricles 

 also. He found in the rabbit, cat, dog 

 and man a bundle of cross-striped muscle 

 fibres, which if experimentally divided pro- 

 duces often a short arhythmic interval, a 

 condition of allorhythmia in which auricles 

 and ventricles beat at diiferent rates. The 

 muscular bundle in question contains no 

 nervous elements. Dr. His was unable to 

 confirm Stanley Kent's results. 



Prof. K. Hiirthle (Breslau) demon- 

 strated his method for determining plethys- 

 mographically the blood pressure in man. 

 An arm is first made bloodless by the 

 Esmarch bandage, and is then introduced 

 into a closely fitting india-rubber case con- 

 nected with a ' Gummi- ' or ' Federmanom- 

 eter.' On re-entry of blood into the arm 

 the pressure rises in about half a minute to 

 its full length, a pulse curve being then re- 

 corded. 



Discussion by Prof. Mosso. 



Dr. K. Kaiser (Heidelberg) gave his 

 views on the causation of the rhythmical 

 contraction of the frog's heart, which he con- 

 siders due to nervous aj)paratus. The heart 

 muscle itself is unable to respond rhythmi- 

 cally to a constant stimulus, as has been 

 hitherto supposed. Dr. Kaiser showed ex- 

 periments on the fi'og's heart in favor of 

 his views. 



Discussion by Mr. Langley, Prof. Burdon 

 Sanderson, Dr. His, Jr., and Prof. Schifi". 



Prof. H. Kronecker (Berne) showed an 

 experiment consisting in the injection of 

 paraffin (of melting point 39° C.) into the 

 peripheral end of the descending coronary 

 artery of a full-grown dog. The ventricles 

 at once entered into fibrillary contractions 



while the auricles continued to beat. Lig- 

 ature of the arterj' does not produce this re- 

 sult. The conclusion drawn was that the 

 normal heartbeat is brought about by the 

 agency of nervous structures, easily aifected 

 by anaemia. 



Dr. E. Magnus (Heidelberg) demon- 

 strated his sphj'mograph, which is applied to 

 the end of a dissected-out artery. Curves, 

 the ordinates of which are proportional to 

 pressures, were shown. 



Discussion by Dr. Cow and Prof. Fi'ed- 

 ericq. 



Prof. N. Zuntz (Berlin) demonstrated 

 his method for estimating the velocity of 

 the blood stream, consisting in the determin- 

 ation of the rate at which blood must be 

 injected into the carotid artery during vagus 

 standstill in order to bring back and main- 

 tain the average blood pressure. 



Dr. A. Beck (Lemberg) gave an account 

 of his experiments with Cj'bulski's photo- 

 hsemotachometer to determine the velocity 

 of the blood stream in the dog's portal vein. 

 He found it to be 2,000-2,800 cubic milli- 

 meters per second, which corresponds to 

 620-780 c. c. per gram of liver tissue in 24 

 hours. There are slight respiratory vari- 

 ations, but only large variations of gen- 

 eral blood pressure produce much effect on 

 velocity of blood stream in the portal vein. 



Afternoon demonstrations and papers 

 (Chairmen, Profs. Tigerstedt and "Weden- 

 sky.) 



Prof. A. Dastre (Paris) discussed the 

 gradual dissolving of fresh fibrin in strong 

 solutions of neutral salts at 40° C, in which 

 process globulins, albumoses and peptones 

 are formed. He analogised this action to 

 that of peptic and pancreatic digestion, of 

 micro-organisms, of oxygenated water, and 

 of sterile distilled water at high tempera- 

 tures and pressures. The hydrolysis of 

 proteids is a general process to which fer- 

 ments are not necessary. Gelatin is simi- 

 larlj^ acted on by salt solutions. 



