What does "Seventy-two only" mean in this line from Dracula? [closed]

In chapter 25 of Dracula by Bram Stoker, Van Helsing says to Mina Harker,

”Good, good! Oh, you so clever lady!" said Van Helsing, enthusiastically, as he stooped and kissed her hand. A moment later he said to me, as calmly as though we had been having a sick room consultation, "Seventy-two only, and in all this excitement. I have hope."

What does "Seventy-two only" mean here?

”Good, good! Oh, you so clever lady!" said Van Helsing, enthusiastically, as he stooped and kissed her hand. A moment later he said to me, as calmly as though we had been having a sick room consultation, "Seventy-two only, and in all this excitement. I have hope."

From The New Annotated Dracula google books

40 This is a truly amazing talent, to take Mina's pulse in a few seconds while kissing her hand! In short, it's another display of Van Hesling's medical quackery.

My sense: her pulse was normal despite the excitement. Not being a Dracula fan, I leave it to others to comment why Mina should have had an abnormal pulse.