Observations on a Liver Mitotic Stimulant

changes result primarily from the excessive uptake of some nutritional element(s) by the tumor (14), and this concept appears to be substantiated in part by a number of nutritional and metabolic studies in tumor-bearing hosts (6, 15, 16, @3,@,4). On the other hand, there appears to be equally valid evidence to support the postulate that systemic changes in the host result from the elaboration of some substance(s) by the tumor (@, 7,8, @1). In vim these various systemic changes are most probably related and to a certain extent dependent upon each other. More striking than their possible in viva relationships, however, is their mutual de pendence upon the presence of a tumor for their initiation. The following study is an attempt to explore more fully certain facets of this tumor-host rela tionship. Since increased mitotic activity is so closely associated with the malignant process it self, investigation of this aspect of the problem seemed particularly interesting, and the present experiments were designed primarily to study the tumor properties which result in an increased mitotic rate in the liver tissue of cancerous animals.