Vincent Chemical Company was an Australian business noted for manufacture of a popular compound analgesic "Vincent's APC" History Dr. Harry John Clayton (ca.1887 – 31 October 1928) of Macquarie Street and medical superintendent of the Royal Prince Alfred Hospital, Sydney, took the headache remedy then in general use, composed of phenacetin and caffeine, and by experimenting with the addition of aspirin, arrived at what became the standard formulation known as A.P.C. powder, or in the Royal Prince Alfred Hospital Pharmacopæia for 1918 as Pulvis Analgesicus. In 1919, at the insistence of his wife, Clayton founded a partnership consisting of Mrs Clayton, E. W. Wills, C. K. Probert (dispenser at the Royal Prince Alfred Hospital), and J. A. Vincent (1890 – 12 June 1933), who had been assistant dispenser at the hospital, and was at that time a pharmacist with a business at Five Dock. Clayton chose the names "Vincent Chemical Company" and "Vincent's APC" to distance himself, as a practicing physician, from any commercial product. During the pneumonic influenza epidemic April to July 1919, he offered many of his customers packages of the compound as A.P.C. powder, which may have been labeled "Vincent's A.P.C." The partnership was incorporated on 11 September 1919 with paid-up capital of £200; £50 from each of the partners; later doubled to total £400. Vincent made up the compound, coloured pink, in premises adjacent to his chemist's shop, as 12 envelopes of powder in a box, or as 24 tablets in a small bottle, and labeled as "pain remedy". Printed instructions for use, supplied gratis by Clayton, were included with each package, bearing the company's trademark "Vincent's APC". The business did not thrive initially, at least in part due to insufficient advertising, and in May 1921 Vincent sold his share of the business (as did Wills) to Probert and Mrs. Clayton, and left for America to train as a dentist, selling his chemist's shop and passing the fledgling manufacturing business to wholesale druggist William Delany. After several months of supplying Clayton and Probert with the product, he was brought into the partnership. In July 1923 the business was re-formed with three owners, Dora Lauraine Clayton, Minnie Probert and Harriett Delany, with joint managers Mr. Probert and Mr. Delany, and in that year the company first showed a profit. They registered their trademark "Vincent's APC" on 21 July 1930, and invested heavily in advertising: £2575 in 1931,