1/2. Separate carefully with a pair of needles a number of 

 filaments from the gills of an oyster or clam. The filaments will 

 remain living in sea-water. Prepare the following solutions. In 

 each experiment transfer several of these filaments with forceps 

 to a clean dry watch-glass; then add several cc. of the solution 

 whose action is to be tested. Examine the filaments in the solutions 

 at frequent intervals and determine as accurately as possible the 

 action of each solution, as follows: 



(a) The character and duration of the ciliary movement. If the 

 cilia are still active at the end of the period cover the watch-glass 

 and examine again next day. 



(b) Are there any visible structural changes as a result of its 

 action ( swelling of cells, breakdown of cilia, etc. ) ? 



a. Pure isotonic solution of the chief chlorides of sea-\vater : 

 m/2 NaCl, m/2 KC1, m/2 MgCL, m/2 CaCL. 



b. Combinations of two chlorides (to show antitoxic action of 

 salts). 



(a) 25 vols, m/2 NaCl -(- i vol. m/2 KC1. 

 (b> 25 vols. m/2 NaCl -|- I vol. m/2 CaCl,. 



( c ) 25 vols. m/2 NaCl -f- i vol. m/2 MgCL. 



c. Combinations of three or four chlorides. 



(a) 25 vols. m/2 NaCl -+- i vol. m/2 KC1 -f T v l- m / 2 CaCl,. 



(b) 25 vols. m/2 NaCl -(- i vol. m/2 KC1 -f i vol. m/2 MgCL. 



( c ) 25 vols. m/2 NaCl -+- i vol. m/2 CaCL + i vol. m/2 MgCL,. 



(d) 25 vols. m/2 NaCl + T v l- m / 2 CaCl, -+- i vol. m/2 KC1 

 -+- i vol. m/2 MgCL. 



Note especially the difference between the pure solution of NaCl 

 and the mi.rtnrcs. \Yhich solutions are the most favorable? Note 

 the differences betwen KC1 and CaCl, or MgCL as antitoxic salt 

 (with NaCl as the toxic salt). The valence of the cation is impor- 

 tant in antitoxic action. 



