Pulse and Respiration. 107 



pulse cycles preceding tetanus shows a decrease of 9 per cent in cycle 

 length, while for the tetanus division the decrease is 2.9 per cent. The 

 post-tetanus division, which includes 21 cycles for comparison, as the 

 pre-tetanus contains 6 and the tetanus 7 cycles, may be averaged in 

 blocks of 7 cycles. Beginning at the left, the decrease in length for 1 

 to 7 inclusive is —2.4, 8 to 14, —3.5, and 15 to 21, —1.4 per cent. 



To provide a convenient numerical [statement for the effect of alcohol 

 by periods on the tetanus pulse, table 19 has been compiled. Here the 

 effect of alcohol is given not on the individual homologous pulse cycles, 

 but the differences have been averaged together to obtain a statement 

 for the pre-tetanus, tetanus, and post-tetanus divisions of the record. 

 This has been done for each experimental hour following the ingestion 

 of alcohol. The method of compiling table 19 may be illustrated as 

 follows : 



In table 18 the differences for the first period of normal days in the 

 pre-tetanus division are +4, —1, +8, +8, +8, and +8; the average of 

 these differences is +6. The corresponding differences for the first 

 period on alcohol days in the same division are shown as —5, —7, — 7, 



— 8, —5, and —3; their average is —6. From this latter average we 

 subtract +6 for the normal days and obtain the difference of —12 as 

 given in table 19. It will be seen, therefore, that the effect of alcohol in 

 period 2 was to reduce the pulse length in the pre-tetanus divisioD by 

 an average of 0.12". In the tetanus division there was a slight increase 

 in the length of 0.01 ", and in the post-tetanus division a decrease 

 which was also slight, 0.02". In periods 3, 4, and 5 a clear tendency 

 is shown for the pulse-length to decrease, this of course meaning a 

 faster pulse rate as a result of the taking of alcohol. These values are 

 given in terms of percentages in the right-hand columns of table 19. 

 The values for the relevant normal were obtained by averaging the pulse- 

 lengths in period 1 of the pre-tetanus, tetanus, and post-tetanus sec- 

 tions of table 18. For example, it will be seen from table 18, period 1, 

 normal, that the relevant normal for the pre-tetanus division may be 

 obtained by adding 103.8 (the average of 104, 107, 104, 103, 104, and 

 101) to 103.7 (the average of the similar values for the first period on 

 the alcohol days, that is, 102, 106, 105, 103, 105, and 101) and dividing 

 the total by 2, giving an average relevant normal for the pre-tetanus 

 division of 103.7. Using this average as a basal value, we may compute 

 the percentile effect of alcohol from the values for differences given in 

 table 19, the percentages for the pre-tetanus division being —11.6, 



— 3.9, —14.5, and —5.8 for periods 2, 3, 4, and 5, respectively. 



By way of summary, therefore, it may be said that in this measure- 

 ment, under the conditions employed, a dose of 30 c.c. of absolute alco- 

 hol produces not only relatively but absolutely a positive rise in pulse 

 rate per minute. The increase in rate is particularly prominent pre- 

 vious to muscular tension. During the period of tension the pulse fails 



