EFFECTS OF CARBON DIOXIDE. 211 



finally, into distilled water and out to the air. The animals were 

 exposed to the steam of pure carbon dioxide for definite lengths 

 of time ranging from one minute to twenty-four hours. They 

 were then removed and the time to the first movement noted. 

 The character of the movements from the beginning of the 

 i -\posure until the animals had recovered was also ob>erved. 



Table I. shows the range, especially in shorter exposure-, in 

 minutes to the firt-t movement. The variations shown are due 

 perhaps t<> individual differences. From an examination of this 

 table it may al>o be seen that when the animal is subjected to the 

 intluenre of pure CO 2 for one minute and then remo\e<l, the time 

 to the hr>t increment varies from four to eiijit minute- with an 

 average of 5.2. With two minutes exposure the time to the tir.-t 

 movement is from two to four minutes with an average of 2.6, 

 With live minutes exposure the variation is .nivater, bein^ from 

 h\e to thirteen minutes with an average of nine. \bo\e li\e 

 minutes exposure, that is from ten minutes to about three hoin>. 

 tin-re is less variation. With five hours expo>ure, then' may be 

 nc. re-ponse, and if any, the movements start immediately upon 

 removal from the gas. 



TAHLI-: II. 



SHU-AIM. 1 IME AND RATE OF THE FlRST MOVEMENT A . TO THE 



GAS FOR DEFINITE PERIODS OF Ti 



Exposure. Time-to First K.it-- "f i 



Movement; , *:r 



Min Average Minute*. 



i 5-i Si 



2 5-1 



4.4 



10 6.3 



!> 5-0 



ao 3-8 



22 6.O 



25 S-O O.2O 



30 4.0 



5-6 0.35 



oo 7-9 



90 1.5 o.oi'. 



120 7.93 O 066 



180 21.5 0.12 



320 6.2 0.017 



5 hours Imnu-'liatr o 



I able 1 1. -hows the average time in minutes to the fir-i nio\ e- 

 meiit and the calculated rate per minute e\po>ure to the gas. 

 The data presented in this table give result- for about two 



