The experiments do establish beyond doubt that some examples of this particular type of sarcoma are true malignant neoplasms in behaviour as well as in appearance. From the present study there is little evidence that massage or repeated sub- total ablation of a tumour affects appreciably the incidence of metastases. Possibly these effects are more readily demonstrated with tumours more prone to metastasize; a definite trend might have been established with the present group of tumours had more animals been used.
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The sentences
The failure to influence the incidence of metastases by mechanical interference or intravenous injection in the present study does not establish that factors necessary for meta- stasis reside solely in the tumour cells. Although the data show no significant relation between metastasis formation and final tumour size, life span or growth rate, the extensive work of Wood and his associates (1954) shows that a large number of animals may be necessary to establish a significant trend.