218 C. J. MARTIN. 
the time being, even within a few minutes of the death of an 
animal. 
Far from considering interference with the vaso-motor centre 
important, in the phenomena of poisoning by this venom, I think 
that the manner in which this centre, and also the vagus centre 4 
escapes, when, as I shall presently show, the activity of a closely 4 
situated group of cells, the respiratory centre is absolutely im 
abeyance, is one of the most remarkable instances of the selective 
operation of a poison, with which I am acquainted. 
Ragotzi' has pointed out that the vaso-motor and vagus centres 
enjoy the same comparative immunity from the action of cobra 
poison. 
That the enormous fall in blood pressure is not due to paralysis 
of any peripheral termination of the splanchic nerves as Feoktistow 
believed was the explanation of the corresponding fall in his expe 
ments with Crotalus poison, is shown by Experiment 5, in which 
stimulation of the peripheral ends of these nerves, produced in the 
late stages of poisoning, as great a rise of pressure propor tionatel, 
as under normal circumstances. Feoktistow does not givé * 
detailed account of the experiments from which he drew his ee 
clusions, but it is not improbable that he had occasioned extensiv? 
thrombosis in the portal area by his intravenous injection, which 
would be an excellent reason why any further peripheral resistance 
in the same area, should not be manifest in the blood pressure 
curve. 
There is a further interesting point shown by the blood pressure 
record, ia those experiments in which I have given at intervals 
two or three injections of venom intravenously. The inject?” 
a very small quantity of venom (00005 gramme per kilo.) pre 
duces a very considerable and immediate fall of blood presi 
which is, however, recovered from. If, after the lapse of 07° sat : 
when the pressure has regained, or almost regained its fom 
1 Virchow’s Archiy., Bd. cxxm., S. 232, 
2 Loe. cit. 
