Was articled at the age of 15 years to David Davies, Surgeon to the Cyfarthfa Iron and Coal Works, Merthyr. At the end of the three years he entered as a student at Grainger's School in the Borough and was educated at the Borough Hospitals. He practised throughout his life at Merthyr Tydfil. The Public Health Act of 1848 gave permissive authority to Local Boards of Health to appoint a fit and proper person to act as Officer of Health to the district, but it was not until 1872 that such an appointment was made obligatory under sanitary authorities. From the days of the Health of Towns Commission, Dyke became an enthusiastic sanitarian, and by means of public lectures he succeeded in bringing home to his fellow-townsmen in Merthyr such a sense of their responsibilities in public health matters that in 1849 it was decided to form a Local Board of Health. Throughout the cholera epidemics of 1849 and 1854 Dyke acted as Medical Officer to the Board of Guardians. In the former year there were nearly 1700 fatal cases, and he himself was attacked by the malady. In 1863, nine years before the appointment was made compulsory, he was elected Medical Officer of Health to the Local Board at a modest salary of twenty guineas per annum, and in 1873 he was appointed to similar office by the Merthyr Rural Sanitary Authority, continuing an official under both bodies in their altered titles (Medical Officer of Health to the Urban and Rural Districts of the Borough of Merthyr Tydfil) until the day of his death. Dyke was a Fellow of the Incorporated Society of Medical Officers of Health and the Sanitary Institute of Great Britain, and a Member of the Epidemiological Society, British Medical Association, and Société française d'Hygiène. He was also a Certifying Factory Surgeon. In 1866 and 1867 he was High Constable of Merthyr. At the time of his death he was the oldest Freemason in Wales, having been initiated in the Loyal Cambrian Lodge No 110 in 1839; he acted as Secretary of the Lodge for twenty years. He had filled the office of Grand Senior Warden in the Provincial Grand Lodge of South Wales and Monmouthshire. During the last six years of his life he did not practise, but devoted himself entirely to his public health duties. He died at Merthyr on January 20th, 1900. Publications:- As a sanitarian of high authority and great initiative Dykes published:- *Annual Reports on the Sanitary Condition of Merthyr Tydfil, prepared for the Local Board of Health by their Medical Officer*, 1-14 (1865-78), 8vo, Merthyr Tydfil, 1866-79. *On the Downward Intermittent Filtration of Sewage, as it is Now in Practical Operation at Troedyrhiw, near Merthyr Tydfil*, 8vo, Merthyr Tydfil 1872; 2nd ed, 1872. *Forms for the Use of Officers of Health. No 7. Diary of Applications to, and Visits by, Medical Officers of Health*. 4to, Merthyr Tydfil 1873. *Report on the Sanitary Condition of the Habitations in the Parishes of Vaynor and Penderyn, and in the Hamlet of Rhigos, part of the District of the Rural Sanitary Board of the Merthyr Tydfil Union*, 1873, 8vo, Merthyr Tydfil, 1873. *Annual Reports on the Sanitary Condition of the Rural District of the Merthyr Tydfil Union to the Rural Sanitary Authority*, 1-6, 1873-8. 8vo, 1874-9. "On the Public Health Bill." - *Brit Med Jour*, 1872, i, 390. *The Work of a Medical Officer of Health, and How to Do it*, 8vo, Merthyr Tydfil, nd. A paper with the title "The Work of a Medical Officer in Health" appeared in the *Brit Med Jour*, 1872, ii, 543. "Missing Links in the Sanitary Administrative Service." - Leamington Congress, 1877. "On the Treatment of Cholera and Diarrhoea in 1832, 1849 and 1854." - *Med Times and Gaz*, 1866, ii, 128.