Two girls laughing<unk>  (from the Greek gelos "laughter") is the study of laughter and its effects on the body, from a psychological and physiological perspective. Its proponents often advocate induction of laughter on therapeutic grounds in alternative medicine. The field of study was pioneered by William F. Fry of Stanford University.
Gelotology
Iatrochemistry
Trinder spot test
Mesomark assay
Diascopy
Roentgen stereophotogrammetry
Buehler test
Fingerstick