Diagnosis has been defined as the act of identifying a disease from a sign and symptom formal a few diagnostic tests we are available to assist the physician who depend on medical history observation and examination. Only recently with the many technological advances in medicine have test become available to assist in making specific diagnosis. Medicine and personal hygiene reach new heights in the 5th century bc at the time of the Greek physician hypocrite.
The Greek recognise this salubrious effects of bathing, fresh air, a good diet exercise which have received renewed attention today. Illness was taught to results from an imbalance between the four humours of the body; blood phlegm yellow bile and black bile. The greek oversize the value of reservation including bodily sign and excretion. The focus however was more on predicting the outcome of venus call prognosis, less and on it diagnosis. A physician reputation depended on accurate prognostic scale predicting who will recover and who will die or how long an illness would last. Hypocrite is credited with establishing the ethical basis of the physicians behaviours and graduating physician still recites the oath ascribed to him. History thing document the value of objectively evaluating all aspect of patient symptoms diet sleep patterns and habits. No funding was considered insignificant and physicians we are encouraged to employ all their sense sight hearing smells taste and touch a making a diagnosis. This principle holds just as true today. The romans made significant adverse is supplying and purifying water and in improving sanitation. Darlin (AD8130- 200) is considered the most influential physician after hypocrite because of his extensive study in anatomy and physiology. His voluminous writing in anatomy and physiology rendered him the ultimate authority in this field until the 16th century. As a first experimental neurologist he describe the cranial nerve and the sympathetic nervous system. He showed that the heart will continue beating when removed from the body and tours does not depend on the nervous system. Many of his view however contain fallacy which remained on challenge for centuries. His description of the heart and its chamber and valve in which he contended that blood passes from the right to the left ventricle by means of invisible power in the interventicular septum, delayed the discovery of blood circulation for 14 centuries. The true nature of the circulation of blood was not recognised until the time of william harvey 1578 to 1657 who publishes finding in Exercitatio anatomical de motu cordis et sanguinis in animalibus ( translated as an anatomical dissection upon the movement of the heart and blood in animal and usually referred to as De motus cordis). From the middle age to the 18th century euroscopy ( examinations of the urine) was a common method for diagnosing illness. The colour of the urine as well as cloudless precipitate and particles in the urine was believed to indicate the cause of the disorder. One of the greatest advance in diagnostic tools was the invention of the compound microscope towards the end of the 16th century by the dutch spectacle Hans Hans Johnsonjohnson and his son zacharias. In the early 17th century galileo constructed a microscope and a telescope. One of the greatest early microscopes antoni van leeuwenhoek 1632- 273, what's the first to see protozoa and bacteria and the first to describe red blood cells. He also demonstrate the capillary anastomasis (network) between arteries and vein that proves harvey to be correct.
Although the mercury thermometer of daniel fahrenheit 1686- 236, appears about 1714 it was not until 1866 that it came into general use as a clinical tools. It was initially 25.4 mm 10 inch long and took five minutes to register a temperature. A pocket version was developed by sir Thoma's Clifford's Albut in 1866. The thermometer was popularized by karl august wunderlich who thought incorrectly that every disease has it own characteristic fever pattern.
Another significant medical advice which greatly improve their ability to diagnose disease of the chest and heart was the invention of the stethoscope in 1816 by Renne Hyacinthe Laennec 1781 -1826. Before this the lung and heart we examine by applying the ear to the chest wall. Laenec initially use a roll of paper enhance sound from the chest and later replaced this instrument with a wooden cylinder. He improve the original monaural (one ears) stetoscope with the binaural device still in current use. Tuberculosis was prominent at the time and the stetoscope allowed laying Laennec to diagnose this condition at an earlier stage than was previously possible.
another significant diagnostic aid was the ophthalmoloscope developed by herman von helmholtz 1821-94, a physician best known for his knowledge of physics and mathematics. With this device the retina and blood vessel could be seen through the pupil allowing the inner eye provide information not only concerning disease of the eye but also about those pertaining to cardiovascular abnormalities and complications of diabetes mellitus.
Perhaps the greatest modern anatomic diagnostic tools is the x-ray discovered in 1895 by the german physicist Willingham Conrad's Roentgen. x-ray have since been commonly referred to as Roentgen rays, and their application eventually lead to the development of computerized tomography and magnetic resonance imaging techniques that are extremely useful modern diagnostic tools.
The training of physician also has undergone significant change over the years. Until the end of the 19th century physician we are trained through lectures and rarely were taught at the patient bed side. This practice was altered by sir william osler one of the most renowned physician of the early 20th century who introduced the practice of instructing student at the bed side of the patient. He emphasized the importance of taking an accurate medical history providing a thorough examination of the patient and closely examine the patient behaviours to gather clues for diagnosis before resulting to laboratory test.
the new encyclopaedia britannica volume 17 knowledge in depth page 204 diagnostic and therapeuticOMOKOSHABAN