On the Latent Period of Muscle Contraction. 



4G5 



only in order to show a sample selected from a large number of curves, 

 and presenting in a fair degree the peculiarities which custom has 

 taught us to expect from the circumstances of the case. 



The first experiments were directed to contrasting the latencies of 

 contractions obtained by stimulating nerve or muscle. 



The length of nerve attached to the preparation which yielded the 

 following measurements was 12'5 millims. The weighting of the 

 muscle was free, and the weights which were suspended sufficiently 

 long before stimulation to cause a proportionate extension increased 

 from lever weight, i.e., 1 grm., up to 100 grms. 



The duration of the latency and of the contraction is expressed in 

 figures indicating the number of double vibrations of the tuning fork 

 used to record the time. Each D.V. corresponds to of a second, 

 which fraction of time therefore forms the unit in the following 

 tables. The altitude of the curve is given in millimetres. 



Table I. — Stimulation of Gastrocnemius Indirect and Direct. 



Muscle . . . 



22 



jS~erve 



21 



M 



20 



N 



19 



M 



18 



N 



17 



M 



16 



N 



15 



M 



14 



N 



13 



M 



12 



N 



11 



M 



10 



N 



9 



M 



8 



N 



7 



M 



6 



N 



5 



M 



4 



N 



3 



M 



2 



jS t 



1 



Weight. 



j- Lever 

 j- 10 grms. -| 



} 20 - i 



} 30 „ j 



} 40 " { 



} 50 - { 

 } 60 „ { 



} » - { 

 } 80 „ { 



} 90 „ { 



}ioo . { 



Length of 

 latency 



hlT^o" 



Length 

 of curve 

 in t!o". 



Altitude 

 in mm. 



2 



24 -8 



25 -0 



2 -75 



23-75 



245 



2 25 



22 -6 



22 3 



3 -05 



21 -5 



22-0 



2 35 



22 -0 



21-0 



3 -10 



21 -3 



21 -3 



2-4 



21 -75 



19-5 



3-25 



21 



20-0 



2 -55 



21 -5 



18 -0 



3-4 



21-5 



18-0 



2-6 



21-5 



16-5 



3 45 



20-5 



17-0 



2 65 



215 



15 '2 



3 5 



20-7 



15-2 



2 -75 



21 -75 



14 4 



3 -55 



20-5 



14-4 



3-05 



22-0 



14-2 



3-65 



21 -35 



14 -2 



3-12 



22-0 



14-5 



3-75 



21 -9 



14 



3 -2 



22 -75 



13 -5 



4-0 



22 -0 



13 -5 



The fact that the increase of weights causes an increase of latency 

 will be at once appreciated after an examination of the table. The 

 latency of contraction under lever weight when the stimulation is 

 direct is '0111", and when indirect "0152". Under 50 grms., direct 

 •0144", indirect '01 91" ; and under 100 grms., direct '0177", indirect 

 •0222". 



