THE SNAPPING TURTLE. 225 
MINIMUM. MAXIMUM. DIFFERENCE. 
40 MoM. 56 MM. 16 M.M. 
37 50 13 
37 50 13 
37 52 15 
37 52 15 
Mean, 37.6 52 14.4 
No. 7. Snapping Turtle. Weight 193 lbs. Temp. of air 74° F. Pulse 30. The 
tube was placed in the left carotid: 
MINIMUM. MAXIMUM. DIFFERENCE. 
30 M.M. 39 M.M. 9 MM. 
36 AT 11 
29 40 11 
3) 4l 10 
31 41 10 
32 43 11 
Mean, 31.5 41.8 10.3 
No. 8. Snapping Turtle. Weight 192 lbs. Temp. of air 74° F. Pulse 30. ‘The 
tube was placed in the left carotid: 
MINIMUM. MAXIMUM. DIFFERENCE. 
39 M.M. 45 M.M. 6 M.M. 
39 44 5 
35 45 10 
30 4] ll 
30 39 9 
35 44 9 
31 40 9 
Mean, 34.1 42.5 8.4 
Upon comparing the above records, it will be seen that the mean of the minimum 
pressures is 33.8; that of the maximum 45.1; and that of the difference 11.3. The first 
number, therefore, represents the average height of a column of mercury sustained by the 
arteries during the diastole of the heart, the average effect of the systole being to lift the 
column 11.3 mm. higher. The statements in regard to the blood-pressures in mammals 
vary so much that it is not easy to find a standard of comparison with those of chelonians ; 
but, assuming M. Bernard’s observations to be correct, we find that the minimum of pres- 
sure in the arteries is nearly the same in mammals of all sizes, being about 
110 mm. in the horse. 
103 m.m. in the dog. 
95 m.m. in the rabbit. 
The rise caused by the heart-beat bears, however, a greater relation to the size of the 
animal, and is noted in the above animals as 65, 12, and 5 respectively. The minimum 
pressure in the artery of the Snapping Turtle is, therefore, about one-third that in the 
VOL. XII.—29 
