Her figure was the perfection of modest grace.

I yielded to the impulse of the moment.

In plain words, I did what you would have done, in my place--I followed her.
She looked round--discovered me--and instantly quickened her pace.
Reaching the westward end of the Strand, she crossed the street and suddenly entered a shop.
I looked through the window, and saw her speak to a respectable elderly person behind the counter, who darted an indignant look at me, and at once led my charming stranger into a back office.

For the moment, I was fool enough to feel puzzled; it was out of my character you will say--but remember, all men are fools when they first fall in love.

After a little while I recovered the use of my senses.