RECENT ADVANCES IN VIRUS PURIFICATION
In going over the recent literature one gets an impression, first, that there is little that is new. Centrifugation, clarification with organic solvents, or precipitation with polyethylene glycole are no longer new. A close look at the methods, however, showed that numerous modifications have been developed to meet specific problems presented by individual viruses. It is these modifications that I shall try to survey.
Perhaps a note of caution would be introduced; in many cases a particular buffer or reducing agent or solvent has been reported as being used. It is clear that the methods succeeds, but it is not always clear whether many variations were tried in selecting the method finally chosen.
I have not tried to limit my remarks to viruses found infecting ornamentals. The diversity of species among ornamental plants is so great that it may only be a matter of chance that a particular virus has not yet been reported in an ornamental.