482 Scientific Proceedings (132) 



TABLE OF RESULTS. 



REFLEX AND NERVE-MUSCLE CONTRACTION HEIGHTS NEAR THE 

 THRESHOLD OF STIMULATION. 



Tenuissimus muscle of the cat. Single induction shocks gradually increased 

 in strength applied to the motor nerve (" Nerve-muscle") or to a sensory 

 nerve for reflex contractions (' 4 Reflex" ). Cat made spinal by pithing the 

 brain. The first three contraction heights only are listed. Magnification 

 approximately ten times. Optical registration. 



Height of record on drum in mm. 









1st step. 



2nd step. 



3d step. 



I 



Nerve -muscle 



(2-22-22) 



9 



18 



25 



II 



Nerve-muscle 



(G-27-2L) 



7 



28 



42 



III 



Nerve-muscle 



(7-10-22) 



28 



40 



57 



IV 



Reflex 



(7-5-22) 



35 



44 



50 



V 



Reflex 



(7-14-22) 



15 



35 



46 



VI 



Reflex 



(7-20-22) 



7 



12 



22 





Nerve-muscle 



6 



10 



21 



VII 



Reflex 



(11-17-22) 



3 



7 



14 





Nerve-muscle 



4 



14 





VIII 



Reflex 



(11-28-22) 



8 



11 



14 





Nerve-muscle 



6 



14 



23 



IX 



Reflex 



(12-1-22) 



13 



26 



32 





Nerve-muscle 



10 



37 





X 



Reflex 



(9-25-22) 



8 



24 



30 





Nerve-muscle 



13 



35 





ilarly stimulated and reflex contractions of the muscle obtained 

 the records show the same step-like increments in contraction 

 heights (Exps. IV and V). 



The intervals between one contraction height and the next are 

 of the same order of magnitude as those of the nerve-muscle 

 preparation. Experiments VI to X are cases where the records 

 have been obtained from the same muscle in the same animal. 

 Exact duplication of records is not to be expected but the cor- 

 respondence in height of increments is close, — notably so in Ex- 

 periment VIII. Each step or increment follows the all-or-none 

 law; if an increment appears at all it appears at its maximum. 

 The records therefore furnish presumptive evidence that in the 

 vicinity of the threshold, reflex contraction does not escape the 

 limitations of the all-or-none conditions under which nerve and 

 muscle fiber act. To this extent the results confirm those of 

 Olmsted and Warner, 4 and are in opposition to those of Graham- 

 Brown. 5 



4 Olmsted and Warner, Amcr. Jour, of Physiol., 1922, lxi, 228. 

 ■> Graham Brown, loc. cit. 



