( 37H ) 



suppose that the luicleus of the intestinal epithelium was per- 

 meable exclusivelij to water, its volume ought to be modified 

 by tlie concentration of the surrounding salt- solution, and the cell 

 in its entirety would experience the influence. What do we observe, 

 however? That the total volume of the cells is independent of the 

 concentration of the surrounding salt-solution. Hence, it follows that, 

 considering the relatively great share the nucleus has in the volume 

 of the cell, the nucleus has also allowed the surrounding salt-solu- 

 tion to pass through it. 



However, if the nucleus were quite impermeable, even to water, 

 the total volume of the cell might still have been independent of 

 the concentration of the surrounding salt-solutions. Considering howe- 

 ver all we have seen concerning the influence of salt-solutions on 

 the volume of spermatozoa, red and white corpuscles, bladder- and 

 oesophagus-epithelium, the impermeability to water is highly impro- 

 bable, and can hardly be supposed, if we consider the part, played 

 by water in the vital processes of the cell. 



II. CILIARY-EPITHELIUM. 



The second sort of epithelium we have investigated is ciliary- 

 epithelium from the trachea. The advantage of this is, that during 

 the whole experiment, we can ascertain whether the object is yet in 

 a live state. After the cells had been, four hours and even longer, 

 in contact with the salt-solutions, cilia were or could be set in move- 

 ment. Also after centrifugalizing ciliary movements could be produced. 



Since the experiments were performed in the same manner as 

 with the intestinal-epithelium, it will suffice to record the results. 



Experiment XXI. 



Ciliary-epithelium from the trachea of a horse just killed. 



The epithelium is distributed in a little Na Cl-solution of O.dJ^. 

 Immediately afterwards equal quantities of it are brought into con- 

 tact with 15 c.c. of a solution of Na CI 0.77o and 1.27o. After 

 half an hour's immersion, 8 c.c. are centrifugalized. 



Salt-solulioDS employed. 



NaCl 0.7°/o 

 " 1.2% 



Volume of the epithelium. 



