ILLUSTRATIONS 



Diagrams whiclj merely illustrate the grouping of apparatus for a par- 

 ticular experiment are omitted from this list. 



Fig. Page 



1. Muscles of left hind limb of frog, dorsal view . . 6 



2. Nerve-muscle preparation 7 



3. Muscle clamp, stand, and nerve-holder .... 8 



4. Tension indicator 25 



5. Stage electrometer ...... 38 



6. Long rheochord . 43 



7. Square rheochord ." .'.".'.' 44 



8. Simple key 45 



9. Short-circuiting key . 46 



11. Pole-changer, early form 49 



12. Rocking key . ...... . . . . . . 50 



14. Ind'uctorium , 54 



15. Platinum electrodes 65 



16. Flat-jawed clamp and round-jawed clamp .... 66 



17. Double clamp . .' 66 



19. Long paper kymograph . 82 



20. Smoker ...... 84 



21. Light muscle lever 86 



22. Tuning fork 87 



23. Noh-pblafizable electrodes 94 



24. Moist chamber .;.......... 95 



25. Hind limb of frog, anterior view 99 



25. Gaskell clamp 103 



26. Electro-magnetic signal 105 



28. Frog board 112 



