STRETCH AND MUSCEE RESPONSE 
183 
with twenty and thirty grams respectively for ten minutes, which 
show when compared with 3 and 4 that where the minute-gram 
unit is constant the sensitizing effect produced is practically the 
same. 
Figure 9. The muscle in this case was first stimulated after 
stretching without removing the ten gram weight, which counter- 
acted the sensitizing properties so that when the weights were 
removed and the muscle was then stimulated the contractions were 
much lower. Compare with figure 5. The tissues used in 5 and 
9 were taken from the same specimen. 
Figures 10 and 11. These are* continuations of figures 7 and 
9, respectively, the latter being almost completely exhausted. 
Each was treated with 0.18 per cent amyl alcohol. The curves 
show its progressive effects. 
The muscles in each of the series 12 to 31 were stimulated 
with a six volt current every twenty seconds. In figures 12 
to 16, the muscles were immersed in normal sodium chloride, 
in 17 to 26, in normal potassium chloride and in 27 to 31 in 
normal calcium chloride. In each case where stretching oc- 
curred the weight was removed before the muscle was stimu- 
lated. 
Figure 12. A typical normal series obtained after mounting 
and stimulating without stretching. 
Figure 13. Similar to 12 except that the muscle was stretched 
with a ten gram weight for ten minutes. The onset and pro- 
gressive effects of fatigue are indicated by the rapid decrease in 
the heights of contraction. 
Figure 14. The muscle in this case was stretched with a ten 
gram weight for twenty minutes, and is to be compared with 
12 and 13. The sensitization of the muscle is indicated by its 
increased and sustained contractions. 
Figure 15. In this case the ten gram weight was applied foi 
one hour. The sustained heights of the contractions which im- 
mediately followed indicate the maximum sensitization of the 
muscle. The tissues used in 14 and 15 were taken from the same 
specimen. 
Figure 16. The ten gram weight was applied in this case for 
three hours. The rapid decrease in the height of contraction and 
its early depletion indicate the progressive effects of fatigue. 
Figure 17. This shows a typical series when immersed in nor- 
mal potassium chloride without stretching. 
Figure 18. A series made from a muscle treated the same as 
