41 
mere accident that these groups are made up of unusually resistant 
mice, is difficult to say. A greater niunber of experiments will have to 
be made to decide positively. Nevertheless, the blank spaces in the 
last column of the table indicate a resistance to the second dose 
and is very suggestive of the idea that the first injections are a 
determining factor in making tliis resistance possible. 
At any rate, it is liighly important in experiments of tliis nature that 
only the results obtained with fresh mice be compared with each other. 
When tliis is done it will be observed (Table XIII) that as small a 
dose as 0.008 mg. per gram body weight may cause death; on the 
other hand, even three times tliis dose kills only 1 mouse out of 14. 
The dose must be 0.040 mg. per gram mouse before any appreciable 
number die, though not a few mice may survive a dose as large as 
0.080 mg. per gram. It is then safe to say that the lethal dose for 
the average mouse is about 0.040 mg. per gram body weight. If the 
lethal dose be placed at 0.040 mg. per gram, then natural 1-adrenahn 
is five times as toxic as arterenol. 
Table XIII. — Toxicity of arterenol hydrochloride. 
Number of 
mouse.a 
Mg. base 
per gm.^ 
Body 
weight. 
Injected. 
Total. ! 
1 
Time. 
i 
1 
Grams. 
Mg. i 
C.c. 1 
67 1 
0. 004 
14. 24 
0. 057 j 
0.06 
Dec. 5, 9.23 a. m 
107 : 1 
0. 004 
15.43 
0.061 
0. 06 
Dec. 9, 9.22 a. m 
68 
0. 008 
16. 50 
0. 132 
0.13 
Dec. 5, 9.28 a. m 
0.008 
18. 34 
0. 146 
0.15 : 
Dec. 9, 9.24 a. m 
69 1 
0. 012 
19.19 
0.240 
0.24 1 
Dec. 5, 9.30 a. m 
109 i 
0. 012 
17. 26 
0. 207 
0.21 ! 
Dec. 9, 9.27 a. m j 
117 ' 
0. 012 
16. 23 
0. 195 
0.20 
Dec. 9, 5.36 p. m | 
179 
0. 012 
14. 47 
0. 173 
0. 17 
Jan. 5 
182 i 
0. 012 
1 
; 19. 77 
0.237 
0.24 
Jan. 5 
185 
0.012 
’ 16. 87 
0. 200 
0.20 
Jan. 5 
70 * 
0. 016 
1 17. 20 
0.275 
0. 27 
Dec. 5, 9.34 a. m 
110 
0. 016 
19. 94 
0. 318 
0.32 
Dec. 9, 9.30 a. m 
118 
1 0. 016 
17. 18 
0.275 
0.27 
Dec. 9, 5.38 p. m 
180 
0. 016 
1 18. 77 
0. 300 
0. 30 
Jan. 5. 
183 
j 0.016 
1 18. 90 
0. 302 
0. 30 
Jan. 5 
186 
0. 016 
14. 54 
0.233 
0. 23 
Jan. 5 
111 
1 0. 020 
10. 56 
0. 211 
0. 21 
Dec. 9, 9.37 a. m 
119 
i 0. 020 
14.80 
0.296 
0. 30 
Dec. 9, 5.40 p. m 
181 
0. 020 
16. 30 
0.326 
0. 33 
Jan. 5 
184 
0.020 
15.92 
0. 318 
0.32 
Jan. 5 
187 
0.020 
15.92 
0. 318 
0. 32 
Jan. 5 
120 
0. 024 
19. 13 
0. 459 
0.46 
Dec. 9, 5.43 p. m 
197 
0. 024 
' 15. 63 
0. 370 
0.37 
Jan. 8, 1.25 p. m ] 
200 
0. 024 
13. 62 
0. 330 
0.33 
Jan. 8, 1.30 p. m | 
203 
0. 024 
13. 32 
0. 320 
0. 32 
Jan. 8, 1.55 p. m : 
Died. 
Dec. 8, 12.45 p. m. 
Dec. 11, 9.40 a. m. (F.), 
Dec. 9, 5.43 p. m. 
Dec. 12. 
a Mice not marked “ W ” or “ F ” were observed by the author to die at the time noted. 
These figures are only approximate. The actual dose is in colmnn “Total Mgs. or C. c. injected.” 
F. Found dead at time noted. 
