Use of tetrazolium salts for electron transport studies in meningopneumonitis. 3. Separation and examination of large and small particles.

Purified suspensions of meningopneumonitis can be separated on potassium tartrate gradient into populations which are 80 to 90% large particles and those which are 90% small particles. Examination of the tetrazole reduction of both particle types indicates that the small particle has associated with it all of the enzymatic activity of the preparation; it also has associated with it most of the infectivity as well.