( 379 ) 



As is well known, the urine-bliidder is lined inside with a fourfold 

 layer of epithelium cells. In a pig- bladder these may be easily elimi- 

 nated. It proved however to be necessary to wash the bladder out 

 well, because not infrequently in the pig, and commonly in the 

 horse, sediment is found on the mucous membrane. 



Experiment XXXI. 

 a pig just killed: 



distributed in a little 



Bladder epithelium of 

 Na Cl-solution of 0.9%. 



Equal quantities of this are left for half an hour in contact with 

 Na Cl-solutious of 0.7'Vo, O.90/0, 1-2% and I.5O/0. After being cen- 

 trifugalized for about two hours, the contents of the tube are well 

 stirred up by means of a platina wire, left an hour to themselves 

 and again centrifugalized. 



From this experiment it appears, that the volume of epithelium 

 decreases regularly and also considerably, with the rise of the con- 

 centration of the salt-solution, and that the figures obtained after 

 an hour and a half's immersion are found to be the same as after 

 an immersion of only half an hour. 



On the ground of similar observations, made on red and white 

 corpuscles and spermatozoa i), we came at the time to the conclusion, 

 that the cells consist of two substances, which behave differently 

 with respect to hygroscopic power; one, the protoplasmatic, which 

 has no share in the hygi-oscopic power of the cell, and the other, 

 th(i intracellular fluid, representing the whole hygroscopic power of 

 the cell. It was then possible by a simple calculation to determine 

 the proportion of the volumina of protoplasmatic to intracellular 



') Proi.-eedings Royal Academy Anisterdam, May 189S. 



26" 



