99-2 



paths become unstable at a d 'fiiiile tcinparatnre, the magnetic cen- 

 trifugal force might make tiiere motions one-sidedly unstable at 

 another temperature. 



If the creation of ordinary resistance in supra-conductors with 

 currents above a certain threshold value, which is fully described 

 in Coram. N". 133, really is a peculiarity of the supra-conducting 

 metal, and not due to disturbances, then the new phenomenon might 

 also be connected with this property. In fact if it were once proved 

 — to use an image already introduced into my paper for the Con- 

 gress in (Chicago — that the vibrators which cause the resistance 

 can only be set in motion when the stream of electrons [)abses them 

 with sufficient rapidity, then it would not be surprising that the 

 magnetic resistance does not arise until the rapidity of the circulating 

 motions of the electi-ons is great enough to cany the atoms with 

 it and set them in rotation, by which they can then disturb the 

 regular motion of the electrons. 



Finally, it is certain that the phenomenon described is connected 

 with the laws of magnetisation of supra-conductors which are as 

 yet unknown. 



Before however drawing detinite conclusions from the new phe- 

 nomenon, it is desirable to gather more experimental information 

 on the subject. 



Physiology. — •■ /\lectroc(irdm/iriiii.s of .-mi-viviiu/ kunian Embri/os". 

 By Prof. J. K. A. Wertheim S.\lomonson. 



(C40mmimicated in the meeling of February "^.S, 1914). 



By the kindness of Dr. H. Tkkub, Professor of Obstetrics and 

 Gynaecology I was enabled to lecord the electrocardiograms of 3 

 human embryos, borj» after operation for extrauterine pregnancy etc. 

 The age of the embryos was given as about 6 weeks, 5 months 

 and 8 weeks and agreed with the length n-.easurements. 



As the operations were performed in the University Institute for 

 Obstetrics and Gynaecology, the embryo had to be sent to my labo- 

 ratory in the University hospital about one mile distant, there being 

 no telecardiographic connection between the two. 



The embryo was put into a bottle containing a warm solution of 

 Ri^ge:?. In the laboratory it was immediately placed in the hot moist 

 chamber, which 1 had formerly used for my experiments with chicken 

 embryos. The leads to the EinthovEiN galvanometer were placed on 

 the upper part of the thorax and on the abdomen. 



