270 



and liigli interference-coloiu-s between crossed nicols. The refrac- 

 tive indices were determined to be : n^ = J ,604 db 0,001 ; 71^ =1 

 J,6i5 i: 0,001 for sodiunibght; the birefringence was about: 0,012. 

 No axial image coidd be observed. The specific gravity of the crys- 

 tals at 25^,1 C. was: d^o = 2,554. 



In a following paper we hope to be able to give an account of 

 the formation and the occurrence of the ^-modification of the spo- 

 duniene in nature, and to review the results so far obtained, also 

 with respect to their geological significance. 



Laboratory for Inorganic Chemistry 

 of the University. 



Groningen, May 1914. 



Physiology. — "On the survival of isolated maimnalian organs 

 with aiitouialic function." By Dr. E. Laqueur. (Communicated 

 l)y Prof. H. J. Hamburger). 



(Communicated in the meeting of April 24, 1914). 



When studying the movements of extii'pated pieces of gut, 1 was 

 struck by the following fact: a piece of gut which had contracted 

 for 9 hours in a Tyrode-solution at 37^ to which oxygen had been 

 added, and which had been left to itself at room-temperature, began 

 to move again the next morning, after being heated and after a 

 renewed addition of oxygen. However frequently such experiments 

 with pieces of gut — in the way suggested l)y Magnus — have 

 been carried out by various investigators, yet the possibility of 

 keeping the gut alive for so long a period seems to be unknown. 



Further researches show, however, that the automatic movements 

 of such pieces of gut are of much longer duration than one day 

 and one night. The longest period, as yet observed by me, runs to 

 more than 3 ireeks. As many as 21 days after the death of the 

 individual the movements of the piece of gut could be observed. 

 This time probably exceeds everything hitherto observed in this 

 respect on mammalian organs working automatically. 



We may compare with this, for instance, how long after the death 

 of the individual the heart can be made to contract. The heart is 

 indeed the only automatic organ, as far as 1 know, on which 

 experiments have been carried out in this direction. Kuliabko, for 

 instance, discovered that when tlic heart of a rabbit, after being 

 kept for 44 hours after death in an ice-chest, was perfused with 

 Locke's solution, contractions again manifested themselves. The heart 



