Back in the laboratory, Kennedy set to work immediately, brushing everything else aside. He began by drawing off a little of Rusty's blood in a tube, very carefully.
"Here, Walter," he said pointing to the little incision he had made.
"Will you take care of him?"
I bound up the wounded leg and gave the poor beast a drink of water. Rusty looked at me gratefully from his big sad brown eyes. He seemed to appreciate our gentleness and to realize that we were trying to help him.
In the meantime, Craig had taken a flask with a rubber stopper. Through one hole in it was fitted a long funnel; through another ran a glass tube. The tube connected with a large U-shaped drying tube filled with calcium chloride, which, in turn, connected with a long open tube with an upturned end.
Into the flask, Craig dropped some pure granulated zinc. Then he covered it with dilute sulphuric acid, poured in through the funnel tube.
"That forms hydrogen gas," he explained to me, "which passes through the drying tube and the ignition tube. Wait a moment until all the air is expelled from the tubes."
He lighted a match and touched it to the open, upturned end. The hydrogen, now escaping freely, was ignited with a pale blue flame.
A few moments later, having extracted something like a serum from the blood he had drawn off from Rusty. He added the extract to the mixture in the flask, pouring it in, also through the funnel tube.
Almost immediately the pale, bluish flame turned to bluish white, and white fumes were formed. In the ignition tube a sort of metallic deposit appeared.
Quickly Craig made one test after another.