166 C. G. Williams and W. H. Waters. [May 12, 



iug. The original beats were restored by washing with normal saline 

 solution. 



In III are two continuous parts of a tracing taken by this method, 

 and should be read from right to left. From 1 the curve is due to 

 the beats of the ventricle after washing with a very small quantity of 

 normal saline solution. At 2 a very small drop of 0*2 per cent. 

 (3 lutidine was allowed to fall on the ventricle, and the changes in the 

 beats, as above described, at once appear, the normal beats being 

 again restored by washing with normal saline solution as at 3. In 

 the particular experiment from which this tracing was taken the 

 drum was slightly irregular, hence the apparent quickening of the 

 beats after the second washing with the saline solution. 



Measurement. — The ventricle was just exposed, and during the in- 

 tervals between the observations the opening was covered with damp 

 blotting paper. Even with this rough method it was found that the 

 injection of 2'0 per cent. /3 lutidine into various lymph spaces or into 

 the cutaneous vein, caused a distinct decrease in the length of the ven- 

 tricle, and this was always attended with a slight paleness. 



From all these cases it cannot but be evident that the introduction 

 of /3 lutidine into the system, enabling it to reach the heart, causes a 

 distinct increase in the tonicity of its ventricle. 



The auricles seem to be affected but very little, and even continue 

 to beat after the ventricle has stopped. 



On Voluntary Muscle. — By a method somewhat similar to that of 

 Dr. Gaskell, the effect of the alkaloid was tried upon ordinary striped 

 muscular tissue. A frog was pithed and placed on its belly in a 

 moist chamber. The tendo-achilles laid bare and tied by fine silk to a 

 lever, the knee-joint being fixed., On washing the muscle with 075 

 per cent, saline solution, as was done to the ventricle, a similar fall of 

 the lever occurred ; but on allowing a drop of 0'5 per cent, ft lutidine 

 (in normal saline) to fall on it, a distinct rise followed. 



Tracing IV illustrates the above, aa, being the abscissa line ; anv 

 increase in the tonicity of the muscle will be indicated by an increase 

 in the distance of the lever's marker from this line. The tracing 

 should be read from right to left. At (1) 075 percent, saline solution 

 was added, and after a short interval the drum allowed to move, a 

 fall of the lever became evident. At (2) and (3) a small drop of 

 0*5 per cent, of the alkaloid was added, and a distinct rise followed ; 

 the washing again with normal saline solution at (4) resulting in a 

 fall. 



(2.) Time of Heart's Beats. — At times we found the results of an 

 experiment undecided, but by far the greater number of them indi- 

 cated a slight slowing after the addition of the alkaloid. It appeared 

 distinctly in the experiments made with strong solutions. 



(3.) Nerves of the Heart. — In all experiments relating to the action 



