In order to study the histological and biological features of experimental gliomas, transplantation experiments were made with the following results.
1) By implanting methylcholanthrene pellets into the brain of various strains of mice and rats, a total of 48 gliomas were produced. They were transplanted into the subcutis of the back of the same strain of animals. Twenty-eight transplanted tumors yielded positive “takes” and of these, 16 gliomas were capable of subsequent transfers through more than 4 generations.
2) Microscopically, the transplants of early generations recapitulated in some measure the features of the histology of the parent tumors. After subsequent transfers, they became more simplified in cell composition and more undifferentiated in cellular appearance, irrespective of their histological types of the primary neoplasms. According to the cytological features of the constituents cells the transplanted tumors over several generations were classified into three types.
3) The transplanted gliomas showed occasionally variation of the histology into mesenchymal tissue tumors. In six cases, the tumors appeared as sarcoma, after they had been transplanted repeatedly. It is argued that this suggests the frequency of the primary tumors which were composed of different component parts, glioma and sarcoma.
4) Experimental gliomas were transplantable into the various parts of the body of the homologous strains and species of animals : the brain, subcutis of the back and tail, anterior chamber of the eye, abdominal cavity, and the kidney. Injections of a suspension of the tumor cells into the vein of the tail also developed multiple tumor growth in various of the body. No significant variations of the histology were visible according to the sites of the tumor growth. The transplantation rate was considerably higher when trnasplanting yonger animals than employing adult ones.
5) Transplantation of experimental gliomas into heterologous strains of animals were also possible. The transplanted tissues showed local growth in the brain, anterior chamber and the subcutis of the back. No variations in the histology were noted between the original and heterologous transplants. In several cases, however, evidences of cell differentiation were observed in the histology of heterologous transplants.
6) Transplantation experiments were also made on the allantoic membrane of the chick eggs. The transplanted cells showed an evidence of growth with highly anaplastic cellular appearance.