Dr. Guillaume endeavors to establish in a recent communication that Buerger's disease, or thrombo-angiitis obliterans, is not a morbid entity. According to Guillaume, it is merely a juvenile type, already known, of arteritis obliterans, previously referred to by Friedländer (1876), von Winiwarter, Zoege von Manteuffel, Dutil and Lamy, and described by Camuset in 1902 under the name of "spontaneous arteritis." It is by no means peculiar to the Jewish race and is not of infectious origin. The disease dates back most commonly to a simple arteritis. Examination of amputated parts shows that, contrary to the opinion of Buerger, there are primary lesions of endarteritis, and that it is these lesions that are the starting point of thrombosis. The veins reveal significant parietal lesions independent of thrombosis. With advancing age these forms develop in the direction of ordinary arteriosclerosis, which is the only type found in aged persons.