OF THE BARK OF ERYTHROPHLEUM GUINENSE. 
647 
nerve-centres, or ( b ) stimulation by the direct action of the drug itself ; ( c ) it was also 
possible that without actually irritating the vagus-roots the casca might increase their 
sensibility to other stimuli, reflex or otherwise. 
Effect on minimum excitability of the Vagus-roots. 
Experiment XXXVII. — March 30. 
A cat, weight 41b., was chloroformed. 
A cannula was inserted into the trachea. 
„ „ left carotid. 
,, „ left saphena vein. 
The right vagus nerve was cut, and its central end placed in a Von Basch’s electrode. 
The left vagus remained intact. A 3 ^ solution of the watery extract was used. 
' 
Respi- 
rations 
Blood- 
Oscilla- 
Pulse in 
in 10 sec. 
pressure. 
tions. 
10 sec. 
m. 
S. 
millims. 
millims. 
0 
Condition before experiment 
4 
105 
1-2 
38 
1 
°1 
The normal excitability of the central end of the 
2 
30/ 
right vagus was then tested ; it was found that 
coil 10° produced slight slowing of the pulse and 
fall of blood-pressure, while the respirations became 
slower and deeper. This was the slightest irritation 
which produced any effect 
2 
100 
3 
30 
3 
30 
Condition after irritation 
2 
110 
1-2 
34 
4 
0 
•5 cub. centim. injected. 
4 
30 
Condition after injection 
3 
140 
1 
34 
Rise of blood-pressure. No alteration of pulse. Re- 
spirations quickened and respiratory oscillations 
increased. 
5 
0 . 
Central end of right vagus irritated. Coil 15° .... 
No effect. 
3| 
140 
1 
34 
6 
0 
Central end of right vagus irritated. Coil 10° .... 
Same effect as before injection. 
21 
135 
1 
38 
7 
0 
Second injection of 1J cub. centim. 
8 
0 
Clot formed and removed. 
g 
0 
Condition before irritation 
3 
120 
2 
43 
9 
30 
Irritation with coil 10° 
0 
120 
2 
40 
The thorax remained in a state of permanent inspi- 
10 
10 
n 
ration during irritation, while the effect on the 
heart and blood-pressure was nil. 
Irritation with coil 6° 
0 
115 
2 
40 
5 J 
No effect on heart. Respiration as before. 
10 
8 
Condition immediately following irritation 
3 
60 
28 
12 
Slowing of pulse. Great ■ fall of blood-pressure. 
Great oscillation. Systole and diastole of same 
length, with no pause between them. 
15 
01 
Irritation with coil 8° 
0 
120 
2 
40 
15 
30/ 
As before there was no effect on the blood-pressure or 
pulse, and there was permanent inspiration during 
the irritation. 
15 
35 
Condition immediately after irritation. See remarks 
1 4 
30 
15 { 
16 
on after effect of coil 6° 
r 4 
irreg. 
16 
0 
Gradual cessation of after effect 
J 2 
100 
7 
22 
16 
30 
After effect ceased 
0| 
120 
2 
35 
17 
0 
Coil 8°. Irritation repeated with same results. 
