TUNEVALL AND LINDNER 



,10 



M-^*^ log nr of pneumococci 

 Hours after + mean error of means 

 inoculation Diff, 



Figure 10. Number of pneumococci in blood at different times after i. p. inocula- 

 tion in hypothermic and normothermic mice. The figures are given as ^Oiogs, with 

 mean errors of the means. Differences, t-values in Student's test, and P-values are 

 also given. 



hours afterwards. The hypothermic mice were kept in this state 

 during the whole experiment, Inbothgroups blood counts were made 

 2, 8, 16, 24, and 36 hours after inoculation. Succumbed mice were 

 autopsied immediately and bacterial counts were then made from 

 heart blood. 



As seen from the figure.bacteremia increased more slowly in the 

 hypothermic mice. This also presented a longer survival time; 

 38.8 ± 1.0 hours as against 28.7 :k 1.6 hours for the normothermic 

 ones (t- value 5.5, P < 0.001). The average numbers of pneumococci 

 per ml blood in the two groups after 2,8, and 16 hours are given in 

 Figure 10 together with results of probability calculations. The form- 

 ula used for testing the significance of differences is : 



Mx - My 



t = 



(x-X)2 + (y-y)2 



"x 



From the figures in the table, the slower increase on the bac- 

 terial numbers among hypothermic mice is verified. After the 16th 

 hour, the differences are no more significant. 



258 



