If you haven't seen it, suggest you take a look at an article by Paschkis, Cantarow, and Stasney Jour. Nat. Canc. Inst.
15:1525 1955. Note--particularly ensuring discussion. These boys maintain they have induced tumors with a "chromatin"
fraction of tumor cells. There has been a good deal of skepticism about their earlier claims and some obviously persists.
Talked with [ . . . ] about it and he is interested in setting up something that might nail the matter one way or the other.
With the proper system we should be able to guarantee exclusion of cells. If you get any ideas let me know.