Methods of Identification

School of Hygiene and Tropical Medicine, and our clinical work has been correlated with mycological studies carried out by Dr. Walker on material from our cases. METHODS OF IDENTIFICATION. GENERAL. The importance of identifying the invading organism as early as possible in the treatment of a patient with tinea cannot be over-emphasised; not only is this important in treatment, but also in measures necessary to prevent the spread of the infection. Four processes of identifying the fungus are available, for use separately or in combination-clinical observation, direct microscopy, examination by Wood's light and mycological culture. CLINICAL OBSERVATION. The various fungi do, to a considerable extent, produce lesions which have certain characteristics enabling a fairly reliable guess to be made in a high proportion of cases of the type of organism responsible. Even to an experienced clinical mycologist these appearances are never completely diagnostic. Additional and very valuable information may be obtained from the clinical history-for example, a duration of twelve months or more would be unusual for infection due to most of the animal types of fungus. More important still would be knowledge of a previous infected person and the identity of the fungus concerned, by whom the patient was infected. The second child in a family, or in a school, is very likely to have the same type of infection as the first child-herein lies the importance of accurate charting of all cases. Indeed, here, too, lies the importance of routine cultures, since, although the culture result may be available too late to influence treatment of a particular primary case, yet secondary cases can be accurately diagnosed at once. One should, therefore, ascertain the presence or absence of other infected persons within the family, the street or locality, or the school, and from previous studies the nature of these infections may be known. Similarly, a history of contact with infected animals (kittens, calves, etc.) gives a clue to the nature of the fungus, provided the fungi endemic in the area are known from past study, e.g., a child who has recently acquired a stray kitten with "bald spots" is almost certain to have a M. canis infection, and a child who has not been out of Belfast for months is most unlikely to acquire T. discoides infection (from cattle). The clinical appearances of the various types of infection are described in the appropriate sections which follow, and the distribution …