Pulse and Respiration. 



103 



of any one experimental day. In figure 13 a curve is shown for each of 

 the six days, the average for the day not including period 1. Light 

 lines and heavy lines have been used to differentiate between the alcohol 

 and non-alcohol days. It is apparent at once, in the pre-tetanus sec- 

 tions of the curve, that the light-line curves for the alcohol days are 

 grouped at a higher level than the three heavy-line or normal curves. 

 In the tetanus section this grouping does not persist and there is great 



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Fig. 13. — Average duration of pulse cycles given in hundredths of a second for three normal 

 and three alcohol days during pre-tetanus, tetanus, and post-tetanus periods, after the 

 control or alcohol dose. 



confusion in the crossing and recrossing of the different curves, although 

 the alcohol curves tend to remain above the normal curves. In the 

 post-tetanus section there is more scattering, the alcohol curves par- 

 ticularly being less closely grouped, but always at a higher level than 

 the normal or heavy curves throughout nearly the entire period repre- 

 sented. In one instance the curve for the second alcohol day crosses 

 the curve for the third normal day near the latter portion of the post- 

 tetanus division. The curve for the last alcohol day, July 4, reaches 

 the highest level in the post-tetanus division and is also, on the average, 

 the highest in the tetanus section; furthermore, it shows the smallest 

 drop immediately after the tetanus. From this diagram it is certain 

 that the relations shown in figure 12 are not due to the fact that any one 

 day exercises a predominating influence upon the shape of the curves. 

 If we selected anyone of the alcohol days and anyone of the normal days 



