198 C. J. MARTIN. 
has elapsed for this to occur, the clamps (c) and (d) are tightened ; 
and (c’) and (d’) opened and the blood allowed to flow through the 
tube 4 for a similar interval of time. The screw clamps ¢ and dv 
are now closed, the clamp forceps replaced on the veins, and the 
whole apparatus disconnected and placed in a vertical position — 
By connecting one of the Y tubes with a pressure bottle contain 
ing mercury the gas first in A and then in B is driven over into 
separate burettes and analysed. % 
‘Sometimes however, instead of using the sip to obtain 
two estimations of the tension of the gases in venous blood, the 
Y¥ tube at the upper end of the instrument has been discarded 
and the two tubes A and B connected with the femoral artery and 
vein respectively. The procedure has then been exactly the same 
as described above, but in these latter cases the tensions of the ' 
gases both in arterial and in venous blood under the same circum 
_ Stances were determined. From a few preliminary experi 
it was ascertained that the interchange of CO, between the blood 
and the mixture of gases contained in the tube was complete it 
five minutes when the mixture of gases contained 5 %, of CO; 
the commencement of the experiment, and in ten to fifteen minut 
when the tube contained air. In the accounts of individ 
experiments the tension of CO, found is expressed in percent 
of an atmosphere. The numbers found when the aéro onome 
tube was filled with air at the commencement of the expel im 
are marked (A), those in which the tube contained 5 i, of ies 
begin with are marked B. 
{n every experiment -000025 gramme of venom per kilogr™ 
of body-weight was at the commencement injected into the jv 
vein. After an interval of one hour an amount of venom ¥ 
in individual cases from -0001 to -001 gramme per aie 
further injected. The reason this particular procedure : 
adopted was in order that the first small injection might PP” 
a sufficiently marked negative phase of coagulability in the 
and that the larger injection might not occasion sudden deaths 
thrombosis, 
* 
¢ se 
