, ILL. THE OPERABILITY and prognosis in patients with carcinoma of the rectum depend on the presence and extent of lymphatic metastases as well as on the degree of local extension of the tumor and the absence of blood-borne metastases to the liver, lungs, bones, brain, etc. The present study was undertaken in an effort to determine the incidence, extent and location of lymph node metastases and the extent of radical removal necessary to insure eradication of all involved nodes.At first, this was done by a very careful dissection of the fresh, surgically removed specimen of carcinoma of the rectum. A full scale drawing was made, and the location of all lymph nodes was carefully noted on it. Between eight and 48 lymph nodes were found in each of 22 specimens examined by gross dissection. Nodes which were thought to be involved with carcinoma were labeled and circled with black ink on the drawing. All nodes were then sectioned and examined microscopically.Recognition of involved nodes by palpation is difficult or impossible when they are small. Four hundred ninety-six nodes from these specimens were examined grossly to determine the presence of metastases. Of the I I I lymph nodes containing carcinoma, only 48 showed any gross change, even in crosssection of the gland. Gabriel, Dukes and Bussey' tried to determine the presence of lymph node metastases in I,242 nodes found in operative specimens of carcinoma of the rectum. Of 337 nodes considered by them to have carcinoma grossly, only I32 were found to be involved when examined microscopically; and of 905 nodes considered to be free of carcinoma, I8 contained carcinoma when examined microscopically.Technic of Examination.-Later, in order to more accurately study all of the lymph nodes, we developed the following technic for examination of surgically removed specimens of carcinoma of the rectum. The ligature on the superior hemorrhoidal artery of the fresh specimen is removed and a small cannula is tied into the artery. The specimen is then perfused with a warm I per cent citrate solution under a pressure of about IOO cm. of water. Ligatures on the smaller vessels are removed so that the blood can be washed out, and as soon as there is a free flow of clear fluid from any open vessel, it is ligated. After one to three hours of perfusion, the specimen is white except for the extrinsic muscles surrounding the anal orifice, and for any small areas where there may have been an extravasation of blood. Such areas can be cleared by very gentle manipulation. After the specimen has become almost entirely white, the artery is injected with red lead. This is done under moderate pressure, using a syringe. The vessel is then tied and the specimen is (Fig. i).A full scale drawing of the bowel, arterial tree and tumor is then made. A section of the tumor is taken and placed in methyl salicylate. The lymph nodes can now be removed, each one can be labeled separately and its position charted exactly in its relation to the artery. These nodes are then placed in methyl salicylate ...