To keep her black bob in perfect condition Phryne uses Koko for the hair. Koko for the hair was made in London, England by a firm called Koko Maricopas Ltd. It first became available around 1888 and was still being sold in 1915.
The claims made for Koko included the "eradication of scurf" and "will positively stop hair from falling out and prevent it turning prematurely grey. Will certainly increase the growth of the hair, and if consistently used will make it bright, soft, and wavy."
The British Medical Association analyzed the Koko preparation and it contained 94% water, 3% alcohol, 2% glycerine along with trace amounts of borax and formaldehyde.
Advertisements were extensive, but inevitably actually said very little. Testimonials were a common method of advertising with Koko "recruiting" famous names including the Greek royal family to support their product. The special offer in the advert below shows enticements to buy scam products have been around for a long time.
In addition, Koko adverts would try to play the honest broker saying "The strong assertions of interested sellers of preparations cannot be relied on, and testimonials, as a rule, cannot be safely taken as genuine unless the position of the writer places him or her above suspicion. We often think that the public must be sick of seeing the eternal - this is the best - attached to every conceivable article which is offered for sale; and for this reason we usually refrain from saying much about Koko, leaving it to our illustrious patrons to speak of its good qualities".