52 ENDOSMOSE. LECT. III. 



with two holes, whose diameter was equal to that of the neck 

 of the instruments. 



In the course of the experiments, the interposed mem- 

 brane in one of the endosmometers was placed in the re- 

 verse position to that of the other : for example, if made of 

 skin, it was so placed that, in one case, the external surface 

 was directed towards the interior of the instrument, whilst, 

 in the other, the internal surface was turned in this direc- 

 tion. 



All the experiments were made at a temperature of from 

 + .12 to + 15 centigr. [ 53-6 Fahr. to 59.] In the 

 greater number of cases they lasted for two hours, and were 

 repeated several times. We took care to provide the two 

 endosmometers employed in the comparative experiments, 

 with two portions of membrane of equal size taken from the 

 same animal, and from two symmetrical regions of the body 

 or organ employed. The liquids used were, besides spring 

 water, the following, of which we give, once for all, the 

 density according to the degrees of Baume's areometer: 



Density of the Liquids in the Endosmometrical Experiments. 



These liquids were usually contained in the interior of 

 the instruments, the water being placed externally. 



In some particular instances we altered the arrangements 

 of the liquids arid instruments, by employing a separate 

 vessel for each endosmometer. We also used another in- 

 strument, of which a figure and description are subjoined: 

 B and c are two cylindrical brass receivers, ground into 



