What does Julia do to try and explain what the speckled band was?

In "The Adventure of the Speckled Band," Julia is the deceased sister of Helen Stoner, a lady who seeks the help of Sherlock and Dr. Watson. Julia was killed at the family home just a few weeks before her wedding day and, in her last moment, cried out about the speckled band:

'Oh, my God! Helen! It was the band! The speckled band!'

As Helen did not understand what she meant by this phrase, Julia tried to explain with a physical gesture:

"She stabbed with her finger into the air in the direction of the doctor's room."

Unfortunately, Helen still did not understand and Julia could not explain any further because she experienced a convulsion, fell unconscious and then died.
It takes the help of Sherlock Holmes to finally unravel the mystery of the speckled band and to reveal that it was, in fact, a poisonous snake which accessed Julia's room through a ventilator hole.