Chicken Sarcomas

CHICKEN SARCOMAS with a "filterable virus" are the object of many interesting studies. Tumors in birds, including chicken sarcomas, are generally not uncommon and are quite diverse. A special place among them is occupied by a group of peculiar chicken sarcomas, usually grouped under the name of Rous sarcomas. They are distinguished by the remarkable property that they can be transferred to another chicken not only by the transplantation of known living sarcomatous cells, but also by inoculating tumor juice filtered through a Berkefeld candle, as well as sarcoma tissue that has been dried and ground into a powder or preserved in glycerin. Such a tumor was first described by Rous in America in 1910; soon after, reports followed from Rous and Murphy and their collaborators, then from the Japanese Fujinami and Oshima, the Italian Pentimalli, and others, regarding the discovery of new examples of chicken sarcomas with similar properties. Usually, chicken sarcomas are highly malignant. In their histological structure, they approach polymorphocellular sarcomas, and among the latter type of tissue, there are usually areas resembling myxosarcoma, and sometimes granulation tissue. General structural features are preserved upon inoculation with a Berkefeld filtrate. Thus, the filtrate of the Rous-Murphy-Tytler osteochondrosarcoma always produces specifically an osteochondrosarcoma, even when inoculated into the muscle mass. Rous sarcomas have aroused enormous interest and lively debate, as the question of a filterable virus (see) as an agent of malignant tumors is connected with them. At the present time, the majority of researchers recognize both the classification of these sarcomas as true neoplasms (blastomas) and the possibility of their inoculation without the transfer of cells (some researchers, especially Nakahara and Teutschländer, pointed to the possibility of the presence of living cells even in the Berkefeld filtrate and dry powder from the tumor). Important new evidence in the above sense was provided by A. Fischer using the tissue culture method. At the same time, it has been established that chicken sarcomas with the properties of Rous sarcomas can also be obtained by the action of chemical agents (indole, arsenic, coal tar) on normal embryonic cells (Carrel, A. Fischer). This circumstance brings Rous sarcomas closer to mammalian tumors and makes it difficult to accept the sarcomatous "virus" as a parasite (an invisible microbe) in the bacteriological sense; many consider this "virus" to be a special chemical agent, as a product of the sarcomatous cell (cf. Bacteriophagy).

Recently, intensive work has been underway to study the biological, chemical, and physicochemical properties of the chicken sarcoma "virus."