An extensive review of the literature on undescended testis and a study of a small personal series of operative cases in the light of impressions gained have indicated that while much is known concerning the etiology, physiology, behavior and fate of the undescended testis. extensive generalizations are to be made with caution and final results in the individual case are hard to foretell. The matter of etiology is very obscure and speculative and need not concern us at present. In the matter of pathology, the undescended testis furnishes equally unconvincing data. In general, it seems established that the abnormally placed testis may be normal or less than normal in size and consistency; rarely it is larger than normal. Spontaneous atrophy is said to be encountered more often after puberty than in childhood. Astley Cooper stated that all cryptorchids had loss of reproductive power, whereupon one of his pupils, a cryptorchid,