_séance_ has been necessary. In this case certain hairs will have received a dose beyond the maximum for safety, and these will be permanently destroyed. For safe working, it is necessary to have a measure of the rays coming from the tube at any given time; and the measure must be constant for every variety of tube. This is obtained by certain colour changes taking place in specially prepared substances, these changes being proportional to the amount of X-rays derived from the tube. The pastilles of Holzknecht have been used for this purpose, but they are a secret preparation, expensive, and not everywhere procurable. Sabouraud has devised small discs made of paper which is the same as that used for screens and is coated with a preparation of platino-cyanide of barium. These discs change in colour in a fixed manner, comparable from time to time with test-colours, and their use makes it impossible, with care, to overstep the limits of safety. E. G. L. SYPHILIS AND CANCER. ETCHEVERRY. (_Ann. de Derm. et de Syph._, August-September, 1904, p. 797.) This research was undertaken in Audry’s Clinique at Toulouse, and the consideration of the connection between these two diseases was directed to the occurrence of lesions on the tongue and buccal mucous membrane. These facts are grouped in three classes, according as: (1) cancer supervened, in syphilitic patients, upon a preceding leucoplakia; (2) without leucoplakia, but in the presence of other local syphilitic lesions, such as gummata, scars of gummata, or of hard chancres; and (3) in the absence of all local signs of syphilis. Thirteen cases of epithelioma developing upon syphilitic leucoplakia are detailed under the first heading. This sequel is relatively frequent. In the second group twenty-two cases are noted. In the third group no direct transformation of syphilitic into epitheliomatous lesions could be established, but the fact of previous syphilis was ascertained in all the fifteen cases quoted. Etcheverry, struck with the singular frequency of association of the two diseases, speculates whether there may not be some direct predisposition in syphilitic patients, as such, to develop cancer. In epithelioma of relatively young patients he states that syphilis may almost always be found as a previous accident. The greater frequency of cancer of the mouth in men than in women coincides with the greater frequency of syphilis in men; according to Fournier, syphilis is eight times more common in males. Etcheverry hazards the suggestion that the cachexia produced by syphilis may be a directly provocative cause of ensuing cancer. As regards the treatment of these mixed cases of syphilis and cancer, the administration of mercury, preferably by injections of calomel, influences favourably the syphilitic element of the disease, and occasionally, as a temporary effort, the epitheliomatous development is checked by this drug. On the other hand,