36 



EXPERIMENTAL PHARMACOLOGY 



Fig. 2. Du Bois Reymond induction coil. 



Fig. 3. Harvard signal magnet. 



Fig. 4. Signal magnet. 





Mm Life record 



6econd5 



Fig. 5. Hale's signal magnet. When this signal magnet is used with a Harvard 



time clock possessing a special adjustment for ten second and minute intervals, three 



time records may be recorded simultaneously. (W. Hale: Jour, of Phar. and Exper. 

 Ther., 1916, viii, p. 445.) 



