Electron microscope observations on the substructure of T-even (T2, T4) head.

New preparative methods have been devised which allow electron microscope observation of T-even head substructure, under conditions of negative staining. Capsomeric constitution of the head shell could so be confirmed and demonstrated for T2 and T4. In addition capsomere size and shell thickness of the head of both phages have been determined and the structural organization of the DNA inside T4 head revealed.