This is a vintage Tono Scalpa Hair Tonic bottle embossed on the front "Tono Scalpa for Dandruff". The antique hair tonic bottle is embossed on the bottom with a number "35" and an upside down "6". The light amethyst colored bottle is mold formed, cork topped. It is uniquely square shaped with a long neck. Tono Scalpa, Inc. was a Richmond, VA company that filed for a patent for their hair dressing in 1919. Advertising from 1919 into the early 1920s promoted that (paraphrased) along with frequent washing, Tono Scalpa would cure dandruff or your money back. Once the Dandruff was gone, hair would regenerate, and in effect, cure baldness. My father, an avid bottle digger, found the old shampoo bottle more than 40 years ago in the ruins of an old homestead in Virginia. It is in nice shape for a dug bottle, there is some scarring on the neck and a couple of small chips. There are air bubbles in the glass and some sediment deposit, especially in one corner. Hopefully that can be removed with a better cleaner or brush than I have. The antique Richmond VA bottle is about 5.75" tall and 2" wide (square).
For more information:
https://books.google.com/books?id=qWAa0MJfQ_0C&pg=PA772&lpg=PA772&dq=about+Tono+Scalpa+Co.,+Inc.+of+Richmond,+VA&source=bl&ots=mii3Za8tUg&sig=ACfU3U0yzcgHnkElUjA6_aWUCVx0paMpYQ&hl=en&sa=X&ved=2ahUKEwjN_uCLqvrzAhVNTTABHam9DeoQ6AF6BAgNEAM#v=onepage&q=about%20Tono%20Scalpa%20Co.%2C%20Inc.%20of%20Richmond%2C%20VA&f=false
https://chroniclingamerica.loc.gov/data/batches/dlc_ewok_ver01/data/sn83045462/00280656616/1919082601/0477.pdf