A Study O F Rous Sarcoma Tissue Grafts in Susceptible and Resistant Chickens

The object of this investigation was to ascertain the sequelae of grafts of Rous chicken sarcoma placed subcutaneously in normal and resistant pure-bred barred Plymouth Rock chickens. Eous and Murphy placed small pieces of Rous sarcoma suboutaneoasly in normal barred Plymouth Rock chkkens, and removed them at intervals along with the surrounding tissue. From microscopic study they found that the central cells of the Rous graft underwent necrosis, but the peripheral cells lived, proliferated, and gave rise to neoplasms that eventually killed the bird. In birds having acquired immunity, the fmdings varied. In some all the cells of the graft became necrotic and no tumor resulted, while in others the peripheral cells gave rise to tumors that eventually regressed and disappeared. In all cases Rous and Murphy were of the opinion that neoplasms resulting from grafts of Rous chicken sarcoma arose from graft cells that lived and proliferated. A graft of Rous chicken sarcoma removed with the surrounding host tissue presents certain diflticulties in histological interpretation. Since the proliferating fibroblasts of the host so closely resemble the tumor cells, there is no definite line of demarcation between graft and host tissue. This junction is also obscured by the presence of great numbers of infiltrating cells. To obviate this difficulty it was proposed to enclose the graft in some type of membrane, permeable to tissue fluids but impermeable to migrating cells, in order that the origin of proliferating cells could be identified. ‘Various membranes were tried, namely, fresh hen peritoneum, f ormalin-fixed hen peritoneum, alcohol-fixed hen peritoneum impregnated with metallic silver, egg yolk and egg shell membrane, fixed sheep-cecum sausage membrane, gold beater’s skin, and Elford’s “gradacol” collodion membranes. Of these membranes, the fixed hen peritoneum impregnated with metallio silver was found to be most satisfactory. This membrane was readily permeable to albumin solutions but impermeable to infiltrating cells. The silver deposit greatly facilitated microscopic identification. The technic of sac grafting was as follows. (1) BiEuered peritmeurn: Sheets of peritoneum from a thin normal hen, freshly killed, were placed in aqueous 2 per cent silver nitrate for